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2015-09-29mtd: provide proper 32/64-bit compat_ioctl() support for BLKPGBrian Norris1-0/+21
After a bit of poking around wondering why my 32-bit user-space can't seem to send a proper ioctl(BLKPG) to an MTD on my 64-bit kernel (ARM64), I noticed that struct blkpg_ioctl_arg is actually pretty unsuitable for use in the ioctl() ABI, due to its use of raw pointers, and its lack of alignment/packing restrictions (32-bit arch'es tend to pack the 4 fields into 4 32-bit words, whereas 64-bit arch'es would add padding after the third int, and make this 6 32-bit words). Anyway, this means BLKPG deserves some special compat_ioctl handling. Do the conversion in a small shim for MTD. block/compat_ioctl.c already has compat support for the block subsystem, but it does so by a re-marshalling data to/from user-space (see compat_blkpg_ioctl()). Personally, I think this approach is cleaner. Tested only on MTD, with an ARM32 user space on an ARM64 kernel. Signed-off-by: Brian Norris <computersforpeace@gmail.com>
2012-10-13UAPI: (Scripted) Disintegrate include/linuxDavid Howells1-59/+0
Signed-off-by: David Howells <dhowells@redhat.com> Acked-by: Arnd Bergmann <arnd@arndb.de> Acked-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Michael Kerrisk <mtk.manpages@gmail.com> Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Acked-by: Dave Jones <davej@redhat.com>
2012-08-01block: add partition resize function to blkpg ioctlVivek Goyal1-0/+1
Add a new operation code (BLKPG_RESIZE_PARTITION) to the BLKPG ioctl that allows altering the size of an existing partition, even if it is currently in use. This patch converts hd_struct->nr_sects into sequence counter because One might extend a partition while IO is happening to it and update of nr_sects can be non-atomic on 32bit machines with 64bit sector_t. This can lead to issues like reading inconsistent size of a partition. Sequence counter have been used so that readers don't have to take bdev mutex lock as we call sector_in_part() very frequently. Now all the access to hd_struct->nr_sects should happen using sequence counter read/update helper functions part_nr_sects_read/part_nr_sects_write. There is one exception though, set_capacity()/get_capacity(). I think theoritically race should exist there too but this patch does not modify set_capacity()/get_capacity() due to sheer number of call sites and I am afraid that change might break something. I have left that as a TODO item. We can handle it later if need be. This patch does not introduce any new races as such w.r.t set_capacity()/get_capacity(). v2: Add CONFIG_LBDAF test to UP preempt case as suggested by Phillip. Signed-off-by: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Phillip Susi <psusi@ubuntu.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2006-04-27linux/blkpg.h needs <linux/compiler.h> for __userDavid Woodhouse1-0/+1
Signed-off-by: David Woodhouse <dwmw2@infradead.org>
2005-04-17Linux-2.6.12-rc2v2.6.12-rc2Linus Torvalds1-0/+57
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!