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2023-10-279p/net: xen: fix false positive printf format overflow warningDominique Martinet1-8/+7
Use the constant to make the compiler happy about this warning: net/9p/trans_xen.c: In function ‘xen_9pfs_front_changed’: net/9p/trans_xen.c:444:39: warning: ‘%d’ directive writing between 1 and 11 bytes into a region of size 8 [-Wformat-overflow=] 444 | sprintf(str, "ring-ref%d", i); | ^~ In function ‘xen_9pfs_front_init’, inlined from ‘xen_9pfs_front_changed’ at net/9p/trans_xen.c:516:8, inlined from ‘xen_9pfs_front_changed’ at net/9p/trans_xen.c:504:13: net/9p/trans_xen.c:444:30: note: directive argument in the range [-2147483644, 2147483646] 444 | sprintf(str, "ring-ref%d", i); | ^~~~~~~~~~~~ net/9p/trans_xen.c:444:17: note: ‘sprintf’ output between 10 and 20 bytes into a destination of size 16 444 | sprintf(str, "ring-ref%d", i); | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~ net/9p/trans_xen.c: In function ‘xen_9pfs_front_changed’: net/9p/trans_xen.c:450:45: warning: ‘%d’ directive writing between 1 and 11 bytes into a region of size 2 [-Wformat-overflow=] 450 | sprintf(str, "event-channel-%d", i); | ^~ In function ‘xen_9pfs_front_init’, inlined from ‘xen_9pfs_front_changed’ at net/9p/trans_xen.c:516:8, inlined from ‘xen_9pfs_front_changed’ at net/9p/trans_xen.c:504:13: net/9p/trans_xen.c:450:30: note: directive argument in the range [-2147483644, 2147483646] 450 | sprintf(str, "event-channel-%d", i); | ^~~~~~~~~~~~~~~~~~ net/9p/trans_xen.c:450:17: note: ‘sprintf’ output between 16 and 26 bytes into a destination of size 16 450 | sprintf(str, "event-channel-%d", i); | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ There is no change in logic: there only are a constant number of rings, and there also already is a BUILD_BUG_ON that checks if that constant goes over 9 as anything bigger would no longer fit the event-channel-%d destination size. In theory having that size as part of the struct means it could be modified by another thread and makes the compiler lose track of possible values for 'i' here, using the constant directly here makes it work. Signed-off-by: Dominique Martinet <asmadeus@codewreck.org> Message-ID: <20231025103445.1248103-3-asmadeus@codewreck.org> Reviewed-by: Christian Schoenebeck <linux_oss@crudebyte.com>
2023-04-029p/xen : Fix use after free bug in xen_9pfs_front_remove due to race conditionZheng Wang1-0/+4
In xen_9pfs_front_probe, it calls xen_9pfs_front_alloc_dataring to init priv->rings and bound &ring->work with p9_xen_response. When it calls xen_9pfs_front_event_handler to handle IRQ requests, it will finally call schedule_work to start the work. When we call xen_9pfs_front_remove to remove the driver, there may be a sequence as follows: Fix it by finishing the work before cleanup in xen_9pfs_front_free. Note that, this bug is found by static analysis, which might be false positive. CPU0 CPU1 |p9_xen_response xen_9pfs_front_remove| xen_9pfs_front_free| kfree(priv) | //free priv | |p9_tag_lookup |//use priv->client Fixes: 71ebd71921e4 ("xen/9pfs: connect to the backend") Signed-off-by: Zheng Wang <zyytlz.wz@163.com> Reviewed-by: Michal Swiatkowski <michal.swiatkowski@linux.intel.com> Signed-off-by: Eric Van Hensbergen <ericvh@kernel.org>
2023-03-01Merge tag '9p-6.3-for-linus-part1' of ↵Linus Torvalds1-17/+31
git://git.kernel.org/pub/scm/linux/kernel/git/ericvh/v9fs Pull 9p updates from Eric Van Hensbergen: - some fixes and cleanup setting up for a larger set of performance patches I've been working on - a contributed fixes relating to 9p/rdma - some contributed fixes relating to 9p/xen * tag '9p-6.3-for-linus-part1' of git://git.kernel.org/pub/scm/linux/kernel/git/ericvh/v9fs: fs/9p: fix error reporting in v9fs_dir_release net/9p: fix bug in client create for .L 9p/rdma: unmap receive dma buffer in rdma_request()/post_recv() 9p/xen: fix connection sequence 9p/xen: fix version parsing fs/9p: Expand setup of writeback cache to all levels net/9p: Adjust maximum MSIZE to account for p9 header
2023-02-249p/xen: fix connection sequenceJuergen Gross1-15/+23
Today the connection sequence of the Xen 9pfs frontend doesn't match the documented sequence. It can work reliably only for a PV 9pfs device having been added at boot time already, as the frontend is not waiting for the backend to have set its state to "XenbusStateInitWait" before reading the backend properties from Xenstore. Fix that by following the documented sequence [1] (the documentation has a bug, so the reference is for the patch fixing that). [1]: https://lore.kernel.org/xen-devel/20230130090937.31623-1-jgross@suse.com/T/#u Link: https://lkml.kernel.org/r/20230130113036.7087-3-jgross@suse.com Fixes: 868eb122739a ("xen/9pfs: introduce Xen 9pfs transport driver") Signed-off-by: Juergen Gross <jgross@suse.com> Reviewed-by: Simon Horman <simon.horman@corigine.com> Signed-off-by: Dominique Martinet <asmadeus@codewreck.org> Signed-off-by: Eric Van Hensbergen <ericvh@kernel.org>
2023-02-249p/xen: fix version parsingJuergen Gross1-2/+8
When connecting the Xen 9pfs frontend to the backend, the "versions" Xenstore entry written by the backend is parsed in a wrong way. The "versions" entry is defined to contain the versions supported by the backend separated by commas (e.g. "1,2"). Today only version "1" is defined. Unfortunately the frontend doesn't look for "1" being listed in the entry, but it is expecting the entry to have the value "1". This will result in failure as soon as the backend will support e.g. versions "1" and "2". Fix that by scanning the entry correctly. Link: https://lkml.kernel.org/r/20230130113036.7087-2-jgross@suse.com Fixes: 71ebd71921e4 ("xen/9pfs: connect to the backend") Signed-off-by: Juergen Gross <jgross@suse.com> Reviewed-by: Simon Horman <simon.horman@corigine.com> Signed-off-by: Dominique Martinet <asmadeus@codewreck.org> Signed-off-by: Eric Van Hensbergen <ericvh@kernel.org>
2023-01-13Merge tag 'for-linus-6.2-rc4-tag' of ↵Linus Torvalds1-2/+1
git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip Pull xen fixes from Juergen Gross: - two cleanup patches - a fix of a memory leak in the Xen pvfront driver - a fix of a locking issue in the Xen hypervisor console driver * tag 'for-linus-6.2-rc4-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip: xen/pvcalls: free active map buffer on pvcalls_front_free_map hvc/xen: lock console list traversal x86/xen: Remove the unused function p2m_index() xen: make remove callback of xen driver void returned
2022-12-15xen: make remove callback of xen driver void returnedDawei Li1-2/+1
Since commit fc7a6209d571 ("bus: Make remove callback return void") forces bus_type::remove be void-returned, it doesn't make much sense for any bus based driver implementing remove callbalk to return non-void to its caller. This change is for xen bus based drivers. Acked-by: Juergen Gross <jgross@suse.com> Signed-off-by: Dawei Li <set_pte_at@outlook.com> Link: https://lore.kernel.org/r/TYCP286MB23238119AB4DF190997075C9CAE39@TYCP286MB2323.JPNP286.PROD.OUTLOOK.COM Signed-off-by: Juergen Gross <jgross@suse.com>
2022-12-139p/client: fix data race on req->statusDominique Martinet1-2/+2
KCSAN reported a race between writing req->status in p9_client_cb and accessing it in p9_client_rpc's wait_event. Accesses to req itself is protected by the data barrier (writing req fields, write barrier, writing status // reading status, read barrier, reading other req fields), but status accesses themselves apparently also must be annotated properly with WRITE_ONCE/READ_ONCE when we access it without locks. Follows: - error paths writing status in various threads all can notify p9_client_rpc, so these all also need WRITE_ONCE - there's a similar read loop in trans_virtio for zc case that also needs READ_ONCE - other reads in trans_fd should be protected by the trans_fd lock and lists state machine, as corresponding writers all are within trans_fd and should be under the same lock. If KCSAN complains on them we likely will have something else to fix as well, so it's better to leave them unmarked and look again if required. Link: https://lkml.kernel.org/r/20221205124756.426350-1-asmadeus@codewreck.org Reported-by: Naresh Kamboju <naresh.kamboju@linaro.org> Suggested-by: Marco Elver <elver@google.com> Acked-by: Marco Elver <elver@google.com> Reviewed-by: Christian Schoenebeck <linux_oss@crudebyte.com> Signed-off-by: Dominique Martinet <asmadeus@codewreck.org>
2022-12-029p/xen: do not memcpy header into req->rcDominique Martinet1-1/+3
while 'h' is packed and can be assumed to match the request payload, req->rc is a struct p9_fcall which is not packed and that memcpy could be wrong. Fix this by copying each fields individually instead. Reported-by: Christian Schoenebeck <linux_oss@crudebyte.com> Reviewed-by: Christian Schoenebeck <linux_oss@crudebyte.com> Suggested-by: Stefano Stabellini <sstabellini@kernel.org> Reviewed-by: Stefano Stabellini <sstabellini@kernel.org> Link: https://lkml.kernel.org/r/alpine.DEB.2.22.394.2211211454540.1049131@ubuntu-linux-20-04-desktop Link: https://lkml.kernel.org/r/20221122001025.119121-1-asmadeus@codewreck.org Signed-off-by: Dominique Martinet <asmadeus@codewreck.org>
2022-11-239p/xen: check logical size for buffer sizeDominique Martinet1-0/+9
trans_xen did not check the data fits into the buffer before copying from the xen ring, but we probably should. Add a check that just skips the request and return an error to userspace if it did not fit Tested-by: Stefano Stabellini <sstabellini@kernel.org> Reviewed-by: Christian Schoenebeck <linux_oss@crudebyte.com> Link: https://lkml.kernel.org/r/20221118135542.63400-1-asmadeus@codewreck.org Signed-off-by: Dominique Martinet <asmadeus@codewreck.org>
2022-10-07net/9p: add __init/__exit annotations to module init/exit funcsXiu Jianfeng1-2/+2
xen transport was missing annotations Link: https://lkml.kernel.org/r/20220909103546.73015-1-xiujianfeng@huawei.com Signed-off-by: Xiu Jianfeng <xiujianfeng@huawei.com> Signed-off-by: Dominique Martinet <asmadeus@codewreck.org>
2022-10-05net/9p: add 'pooled_rbuffers' flag to struct p9_trans_moduleChristian Schoenebeck1-0/+1
This is a preparatory change for the subsequent patch: the RDMA transport pulls the buffers for its 9p response messages from a shared pool. [1] So this case has to be considered when choosing an appropriate response message size in the subsequent patch. Link: https://lore.kernel.org/all/Ys3jjg52EIyITPua@codewreck.org/ [1] Link: https://lkml.kernel.org/r/79d24310226bc4eb037892b5c097ec4ad4819a03.1657920926.git.linux_oss@crudebyte.com Signed-off-by: Christian Schoenebeck <linux_oss@crudebyte.com> Signed-off-by: Dominique Martinet <asmadeus@codewreck.org>
2022-07-099p: Add client parameter to p9_req_put()Kent Overstreet1-1/+1
This is to aid in adding mempools, in the next patch. Link: https://lkml.kernel.org/r/20220704014243.153050-2-kent.overstreet@gmail.com Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com> Cc: Eric Van Hensbergen <ericvh@gmail.com> Cc: Latchesar Ionkov <lucho@ionkov.net> Signed-off-by: Dominique Martinet <asmadeus@codewreck.org>
2022-05-27xen: switch gnttab_end_foreign_access() to take a struct page pointerJuergen Gross1-4/+4
Instead of a virtual kernel address use a pointer of the associated struct page as second parameter of gnttab_end_foreign_access(). Most users have that pointer available already and are creating the virtual address from it, risking problems in case the memory is located in highmem. gnttab_end_foreign_access() itself won't need to get the struct page from the address again. Suggested-by: Jan Beulich <jbeulich@suse.com> Signed-off-by: Juergen Gross <jgross@suse.com> Reviewed-by: Jan Beulich <jbeulich@suse.com> Signed-off-by: Juergen Gross <jgross@suse.com>
2022-03-16xen/grant-table: remove readonly parameter from functionsJuergen Gross1-4/+4
The gnttab_end_foreign_access() family of functions is taking a "readonly" parameter, which isn't used. Remove it from the function parameters. Signed-off-by: Juergen Gross <jgross@suse.com> Link: https://lore.kernel.org/r/20220311103429.12845-3-jgross@suse.com Reviewed-by: Jan Beulich <jbeulich@suse.com> Acked-by: Christian Schoenebeck <qemu_oss@crudebyte.com> Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
2022-03-07xen/9p: use alloc/free_pages_exact()Juergen Gross1-8/+6
Instead of __get_free_pages() and free_pages() use alloc_pages_exact() and free_pages_exact(). This is in preparation of a change of gnttab_end_foreign_access() which will prohibit use of high-order pages. By using the local variable "order" instead of ring->intf->ring_order in the error path of xen_9pfs_front_alloc_dataring() another bug is fixed, as the error path can be entered before ring->intf->ring_order is being set. By using alloc_pages_exact() the size in bytes is specified for the allocation, which fixes another bug for the case of order < (PAGE_SHIFT - XEN_PAGE_SHIFT). This is part of CVE-2022-23041 / XSA-396. Reported-by: Simon Gaiser <simon@invisiblethingslab.com> Signed-off-by: Juergen Gross <jgross@suse.com> Reviewed-by: Jan Beulich <jbeulich@suse.com> --- V4: - new patch
2022-01-109p/xen: autoload when xenbus service is availableThomas Weißschuh1-0/+1
Link: https://lkml.kernel.org/r/20211103193823.111007-4-linux@weissschuh.net Signed-off-by: Thomas Weißschuh <linux@weissschuh.net> Signed-off-by: Dominique Martinet <asmadeus@codewreck.org>
2021-11-039p: fix file headersDominique Martinet1-24/+1
- add missing SPDX-License-Identifier - remove (sometimes incorrect) file name from file header Link: http://lkml.kernel.org/r/20211102134608.1588018-2-dominique.martinet@atmark-techno.com Signed-off-by: Dominique Martinet <asmadeus@codewreck.org>
2021-11-03net/9p: autoload transport modulesThomas Weißschuh1-0/+1
Automatically load transport modules based on the trans= parameter passed to mount. This removes the requirement for the user to know which module to use. Link: http://lkml.kernel.org/r/20211017134611.4330-1-linux@weissschuh.net Signed-off-by: Thomas Weißschuh <linux@weissschuh.net> Signed-off-by: Dominique Martinet <asmadeus@codewreck.org>
2021-07-279p/xen: Fix end of loop tests for list_for_each_entryHarshvardhan Jha1-2/+2
This patch addresses the following problems: - priv can never be NULL, so this part of the check is useless - if the loop ran through the whole list, priv->client is invalid and it is more appropriate and sufficient to check for the end of list_for_each_entry loop condition. Link: http://lkml.kernel.org/r/20210727000709.225032-1-harshvardhan.jha@oracle.com Signed-off-by: Harshvardhan Jha <harshvardhan.jha@oracle.com> Reviewed-by: Stefano Stabellini <sstabellini@kernel.org> Tested-by: Stefano Stabellini <sstabellini@kernel.org> Cc: <stable@vger.kernel.org> Signed-off-by: Dominique Martinet <asmadeus@codewreck.org>
2020-10-099p/xen: Fix format argument warningYe Bin1-2/+2
Fix follow warnings: [net/9p/trans_xen.c:454]: (warning) %u in format string (no. 1) requires 'unsigned int' but the argument type is 'int'. [net/9p/trans_xen.c:460]: (warning) %u in format string (no. 1) requires 'unsigned int' but the argument type is 'int'. Link: http://lkml.kernel.org/r/20201009080552.89918-1-yebin10@huawei.com Reported-by: Hulk Robot <hulkci@huawei.com> Signed-off-by: Ye Bin <yebin10@huawei.com> Signed-off-by: Dominique Martinet <asmadeus@codewreck.org>
2020-08-24treewide: Use fallthrough pseudo-keywordGustavo A. R. Silva1-1/+1
Replace the existing /* fall through */ comments and its variants with the new pseudo-keyword macro fallthrough[1]. Also, remove unnecessary fall-through markings when it is the case. [1] https://www.kernel.org/doc/html/v5.7/process/deprecated.html?highlight=fallthrough#implicit-switch-case-fall-through Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
2020-06-029p/xen: increase XEN_9PFS_RING_ORDERStefano Stabellini1-27/+34
Increase XEN_9PFS_RING_ORDER to 9 for performance reason. Order 9 is the max allowed by the protocol. We can't assume that all backends will support order 9. The xenstore property max-ring-page-order specifies the max order supported by the backend. We'll use max-ring-page-order for the size of the ring. This means that the size of the ring is not static (XEN_FLEX_RING_SIZE(9)) anymore. Change XEN_9PFS_RING_SIZE to take an argument and base the calculation on the order chosen at setup time. Finally, modify p9_xen_trans.maxsize to be divided by 4 compared to the original value. We need to divide it by 2 because we have two rings coming off the same order allocation: the in and out rings. This was a mistake in the original code. Also divide it further by 2 because we don't want a single request/reply to fill up the entire ring. There can be multiple requests/replies outstanding at any given time and if we use the full ring with one, we risk forcing the backend to wait for the client to read back more replies before continuing, which is not performant. Link: http://lkml.kernel.org/r/20200521193242.15953-1-sstabellini@kernel.org Signed-off-by: Stefano Stabellini <stefano.stabellini@xilinx.com> Signed-off-by: Dominique Martinet <dominique.martinet@cea.fr>
2019-07-13Merge tag '9p-for-5.3' of git://github.com/martinetd/linuxLinus Torvalds1-1/+7
Pull 9p updates from Dominique Martinet: "Two small fixes to properly cleanup the 9p transports list if virtio/xen module initialization fail. 9p might otherwise try to access memory from a module that failed to register got freed" * tag '9p-for-5.3' of git://github.com/martinetd/linux: 9p/xen: Add cleanup path in p9_trans_xen_init 9p/virtio: Add cleanup path in p9_virtio_init
2019-05-159p/xen: Add cleanup path in p9_trans_xen_initYueHaibing1-1/+7
If xenbus_register_frontend() fails in p9_trans_xen_init, we should call v9fs_unregister_trans() to do cleanup. Link: http://lkml.kernel.org/r/20190430143933.19368-1-yuehaibing@huawei.com Cc: stable@vger.kernel.org Fixes: 868eb122739a ("xen/9pfs: introduce Xen 9pfs transport driver") Signed-off-by: YueHaibing <yuehaibing@huawei.com> Signed-off-by: Dominique Martinet <dominique.martinet@cea.fr>
2019-01-239p: mark expected switch fall-throughGustavo A. R. Silva1-1/+1
In preparation to enabling -Wimplicit-fallthrough, mark switch cases where we are expecting to fall through. This patch fixes the following warning: net/9p/trans_xen.c:514:6: warning: this statement may fall through [-Wimplicit-fallthrough=] Warning level 3 was used: -Wimplicit-fallthrough=3 This patch is part of the ongoing efforts to enabling -Wimplicit-fallthrough Link: http://lkml.kernel.org/r/20190123071632.GA8039@embeddedor Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com> Signed-off-by: Dominique Martinet <dominique.martinet@cea.fr>
2018-09-079p: Add refcount to p9_req_tTomas Bortoli1-0/+1
To avoid use-after-free(s), use a refcount to keep track of the usable references to any instantiated struct p9_req_t. This commit adds p9_req_put(), p9_req_get() and p9_req_try_get() as wrappers to kref_put(), kref_get() and kref_get_unless_zero(). These are used by the client and the transports to keep track of valid requests' references. p9_free_req() is added back and used as callback by kref_put(). Add SLAB_TYPESAFE_BY_RCU as it ensures that the memory freed by kmem_cache_free() will not be reused for another type until the rcu synchronisation period is over, so an address gotten under rcu read lock is safe to inc_ref() without corrupting random memory while the lock is held. Link: http://lkml.kernel.org/r/1535626341-20693-1-git-send-email-asmadeus@codewreck.org Co-developed-by: Dominique Martinet <dominique.martinet@cea.fr> Signed-off-by: Tomas Bortoli <tomasbortoli@gmail.com> Reported-by: syzbot+467050c1ce275af2a5b8@syzkaller.appspotmail.com Signed-off-by: Dominique Martinet <dominique.martinet@cea.fr>
2018-09-079p: embed fcall in req to round down buffer allocsDominique Martinet1-6/+6
'msize' is often a power of two, or at least page-aligned, so avoiding an overhead of two dozen bytes for each allocation will help the allocator do its work and reduce memory fragmentation. Link: http://lkml.kernel.org/r/1533825236-22896-1-git-send-email-asmadeus@codewreck.org Suggested-by: Matthew Wilcox <willy@infradead.org> Signed-off-by: Dominique Martinet <dominique.martinet@cea.fr> Reviewed-by: Greg Kurz <groug@kaod.org> Acked-by: Jun Piao <piaojun@huawei.com> Cc: Matthew Wilcox <willy@infradead.org>
2018-08-279p/xen: fix check for xenbus_read error in front_probeDominique Martinet1-2/+2
If the xen bus exists but does not expose the proper interface, it is possible to get a non-zero length but still some error, leading to strcmp failing trying to load invalid memory addresses e.g. fffffffffffffffe. There is then no need to check length when there is no error, as the xenbus driver guarantees that the string is nul-terminated. Link: http://lkml.kernel.org/r/1534236007-10170-1-git-send-email-asmadeus@codewreck.org Signed-off-by: Dominique Martinet <dominique.martinet@cea.fr> Reviewed-by: Stefano Stabellini <sstabellini@kernel.org> Cc: Eric Van Hensbergen <ericvh@gmail.com> Cc: Latchesar Ionkov <lucho@ionkov.net>
2018-08-139p: fix multiple NULL-pointer-dereferencesTomas Bortoli1-0/+3
Added checks to prevent GPFs from raising. Link: http://lkml.kernel.org/r/20180727110558.5479-1-tomasbortoli@gmail.com Signed-off-by: Tomas Bortoli <tomasbortoli@gmail.com> Reported-by: syzbot+1a262da37d3bead15c39@syzkaller.appspotmail.com Cc: stable@vger.kernel.org Signed-off-by: Dominique Martinet <dominique.martinet@cea.fr>
2018-06-08net/9p/trans_xen.c: don't inclide rwlock.h directlySebastian Andrzej Siewior1-1/+0
rwlock.h should not be included directly. Instead linux/splinlock.h should be included. One thing it does is to break the RT build. Link: http://lkml.kernel.org/r/20180504100319.11880-1-bigeasy@linutronix.de Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Cc: Eric Van Hensbergen <ericvh@gmail.com> Cc: Ron Minnich <rminnich@sandia.gov> Cc: Latchesar Ionkov <lucho@ionkov.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-05-10net/9p: fix spelling mistake: "suspsend" -> "suspend"Colin Ian King1-1/+1
Trivial fix to spelling mistake in dev_warn message text Signed-off-by: Colin Ian King <colin.king@canonical.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-01-159p: add missing module license for xen transportStephen Hemminger1-0/+4
The 9P of Xen module is missing required license and module information. See https://bugzilla.kernel.org/show_bug.cgi?id=198109 Reported-by: Alan Bartlett <ajb@elrepo.org> Fixes: 868eb122739a ("xen/9pfs: introduce Xen 9pfs transport driver") Signed-off-by: Stephen Hemminger <stephen@networkplumber.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-10-24net/9p: Switch to wait_event_killable()Tuomas Tynkkynen1-2/+2
Because userspace gets Very Unhappy when calls like stat() and execve() return -EINTR on 9p filesystem mounts. For instance, when bash is looking in PATH for things to execute and some SIGCHLD interrupts stat(), bash can throw a spurious 'command not found' since it doesn't retry the stat(). In practice, hitting the problem is rare and needs a really slow/bogged down 9p server. Cc: stable@vger.kernel.org Signed-off-by: Tuomas Tynkkynen <tuomas@tuxera.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2017-05-18xen/9pfs: p9_trans_xen_init and p9_trans_xen_exit can be staticWei Yongjun1-2/+2
Fixes the following sparse warnings: net/9p/trans_xen.c:528:5: warning: symbol 'p9_trans_xen_init' was not declared. Should it be static? net/9p/trans_xen.c:540:6: warning: symbol 'p9_trans_xen_exit' was not declared. Should it be static? Signed-off-by: Wei Yongjun <weiyongjun1@huawei.com> Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>
2017-05-18xen/9pfs: fix return value check in xen_9pfs_front_probe()Wei Yongjun1-2/+2
In case of error, the function xenbus_read() returns ERR_PTR() and never returns NULL. The NULL test in the return value check should be replaced with IS_ERR(). Fixes: 71ebd71921e4 ("xen/9pfs: connect to the backend") Signed-off-by: Wei Yongjun <weiyongjun1@huawei.com> Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>
2017-05-02xen/9pfs: initialize len to 0 to detect xenbus_read errorsStefano Stabellini1-1/+1
In order to use "len" to check for xenbus_read errors properly, we need to initialize len to 0 before passing it to xenbus_read. CC: dan.carpenter@oracle.com CC: jgross@suse.com CC: boris.ostrovsky@oracle.com CC: Eric Van Hensbergen <ericvh@gmail.com> CC: Ron Minnich <rminnich@sandia.gov> CC: Latchesar Ionkov <lucho@ionkov.net> CC: v9fs-developer@lists.sourceforge.net Signed-off-by: Stefano Stabellini <stefano@aporeto.com> Reviewed-by: Juergen Gross <jgross@suse.com> Signed-off-by: Juergen Gross <jgross@suse.com>
2017-05-02xen/9pfs: receive responsesStefano Stabellini1-0/+56
Upon receiving a notification from the backend, schedule the p9_xen_response work_struct. p9_xen_response checks if any responses are available, if so, it reads them one by one, calling p9_client_cb to send them up to the 9p layer (p9_client_cb completes the request). Handle the ring following the Xen 9pfs specification. CC: groug@kaod.org CC: jgross@suse.com CC: Eric Van Hensbergen <ericvh@gmail.com> CC: Ron Minnich <rminnich@sandia.gov> CC: Latchesar Ionkov <lucho@ionkov.net> CC: v9fs-developer@lists.sourceforge.net Signed-off-by: Stefano Stabellini <stefano@aporeto.com> Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> Reviewed-by: Juergen Gross <jgross@suse.com> Signed-off-by: Juergen Gross <jgross@suse.com>
2017-05-02xen/9pfs: send requests to the backendStefano Stabellini1-2/+85
Implement struct p9_trans_module create and close functions by looking at the available Xen 9pfs frontend-backend connections. We don't expect many frontend-backend connections, thus walking a list is OK. Send requests to the backend by copying each request to one of the available rings (each frontend-backend connection comes with multiple rings). Handle the ring and notifications following the 9pfs specification. If there are not enough free bytes on the ring for the request, wait on the wait_queue: the backend will send a notification after consuming more requests. CC: groug@kaod.org CC: jgross@suse.com CC: Eric Van Hensbergen <ericvh@gmail.com> CC: Ron Minnich <rminnich@sandia.gov> CC: Latchesar Ionkov <lucho@ionkov.net> CC: v9fs-developer@lists.sourceforge.net Signed-off-by: Stefano Stabellini <stefano@aporeto.com> Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> Reviewed-by: Juergen Gross <jgross@suse.com> Signed-off-by: Juergen Gross <jgross@suse.com>
2017-05-02xen/9pfs: connect to the backendStefano Stabellini1-0/+281
Implement functions to handle the xenbus handshake. Upon connection, allocate the rings according to the protocol specification. Initialize a work_struct and a wait_queue. The work_struct will be used to schedule work upon receiving an event channel notification from the backend. The wait_queue will be used to wait when the ring is full and we need to send a new request. CC: groug@kaod.org CC: boris.ostrovsky@oracle.com CC: jgross@suse.com CC: Eric Van Hensbergen <ericvh@gmail.com> CC: Ron Minnich <rminnich@sandia.gov> CC: Latchesar Ionkov <lucho@ionkov.net> CC: v9fs-developer@lists.sourceforge.net Signed-off-by: Stefano Stabellini <stefano@aporeto.com> Reviewed-by: Juergen Gross <jgross@suse.com> Signed-off-by: Juergen Gross <jgross@suse.com>
2017-05-02xen/9pfs: introduce Xen 9pfs transport driverStefano Stabellini1-0/+125
Introduce the Xen 9pfs transport driver: add struct xenbus_driver to register as a xenbus driver and add struct p9_trans_module to register as v9fs driver. All functions are empty stubs for now. CC: groug@kaod.org CC: jgross@suse.com CC: Eric Van Hensbergen <ericvh@gmail.com> CC: Ron Minnich <rminnich@sandia.gov> CC: Latchesar Ionkov <lucho@ionkov.net> CC: v9fs-developer@lists.sourceforge.net Signed-off-by: Stefano Stabellini <stefano@aporeto.com> Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> Reviewed-by: Juergen Gross <jgross@suse.com> Signed-off-by: Juergen Gross <jgross@suse.com>