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authorBoaz Harrosh <bharrosh@panasas.com>2009-12-01 18:36:21 +0300
committerJames Bottomley <James.Bottomley@suse.de>2009-12-10 17:54:17 +0300
commit5d0961fd1f25e117f907f3af3aaa870637049252 (patch)
tree1eb877e773c511b3da68cab9da4ae0d0e0ee7369 /drivers/scsi/osd
parentaeab3fd7b865bc4086a80a83cfdd67dded3b41a0 (diff)
downloadlinux-5d0961fd1f25e117f907f3af3aaa870637049252.tar.xz
[SCSI] libosd: Fix blk_put_request locking again
So libosd has decided to sacrifice some code simplicity for the sake of a clean API. One of these things is the possibility for users to call osd_end_request, in any condition at any state. This opens up some problems with calling blk_put_request when out-side of the completion callback but calling __blk_put_request when detecting a from-completion state. The current hack was working just fine until exofs decided to operate on all devices in parallel and wait for the sum of the requests, before deallocating all osd-requests at once. There are two new possible cases 1. All request in a group are deallocated as part of the last request's async-done, request_queue is locked. 2. All request in a group where executed asynchronously, but de-allocation was delayed to after the async-done, in the context of another thread. Async execution but request_queue is not locked. The solution I chose was to separate the deallocation of the osd_request which has the information users need, from the deallocation of the internal(2) requests which impose the locking problem. The internal block-requests are freed unconditionally inside the async-done-callback, when we know the queue is always locked. If at osd_end_request time we still have a bock-request, then we know it did not come from within an async-done-callback and we can call the regular blk_put_request. The internal requests were used for carrying error information after execution. This information is now copied to osd_request members for later analysis by user code. The external API and behaviour was unchanged, except now it really supports what was previously advertised. Reported-by: Vineet Agarwal <checkout.vineet@gmail.com> Signed-off-by: Boaz Harrosh <bharrosh@panasas.com> Cc: Stable Tree <stable@kernel.org> Signed-off-by: James Bottomley <James.Bottomley@suse.de>
Diffstat (limited to 'drivers/scsi/osd')
-rw-r--r--drivers/scsi/osd/osd_initiator.c88
1 files changed, 47 insertions, 41 deletions
diff --git a/drivers/scsi/osd/osd_initiator.c b/drivers/scsi/osd/osd_initiator.c
index 950202a70bcf..24223473f573 100644
--- a/drivers/scsi/osd/osd_initiator.c
+++ b/drivers/scsi/osd/osd_initiator.c
@@ -432,30 +432,23 @@ static void _osd_free_seg(struct osd_request *or __unused,
seg->alloc_size = 0;
}
-static void _put_request(struct request *rq , bool is_async)
+static void _put_request(struct request *rq)
{
- if (is_async) {
- WARN_ON(rq->bio);
- __blk_put_request(rq->q, rq);
- } else {
- /*
- * If osd_finalize_request() was called but the request was not
- * executed through the block layer, then we must release BIOs.
- * TODO: Keep error code in or->async_error. Need to audit all
- * code paths.
- */
- if (unlikely(rq->bio))
- blk_end_request(rq, -ENOMEM, blk_rq_bytes(rq));
- else
- blk_put_request(rq);
- }
+ /*
+ * If osd_finalize_request() was called but the request was not
+ * executed through the block layer, then we must release BIOs.
+ * TODO: Keep error code in or->async_error. Need to audit all
+ * code paths.
+ */
+ if (unlikely(rq->bio))
+ blk_end_request(rq, -ENOMEM, blk_rq_bytes(rq));
+ else
+ blk_put_request(rq);
}
void osd_end_request(struct osd_request *or)
{
struct request *rq = or->request;
- /* IMPORTANT: make sure this agrees with osd_execute_request_async */
- bool is_async = (or->request->end_io_data == or);
_osd_free_seg(or, &or->set_attr);
_osd_free_seg(or, &or->enc_get_attr);
@@ -463,20 +456,34 @@ void osd_end_request(struct osd_request *or)
if (rq) {
if (rq->next_rq) {
- _put_request(rq->next_rq, is_async);
+ _put_request(rq->next_rq);
rq->next_rq = NULL;
}
- _put_request(rq, is_async);
+ _put_request(rq);
}
_osd_request_free(or);
}
EXPORT_SYMBOL(osd_end_request);
+static void _set_error_resid(struct osd_request *or, struct request *req,
+ int error)
+{
+ or->async_error = error;
+ or->req_errors = req->errors ? : error;
+ or->sense_len = req->sense_len;
+ if (or->out.req)
+ or->out.residual = or->out.req->resid_len;
+ if (or->in.req)
+ or->in.residual = or->in.req->resid_len;
+}
+
int osd_execute_request(struct osd_request *or)
{
- return or->async_error =
- blk_execute_rq(or->request->q, NULL, or->request, 0);
+ int error = blk_execute_rq(or->request->q, NULL, or->request, 0);
+
+ _set_error_resid(or, or->request, error);
+ return error;
}
EXPORT_SYMBOL(osd_execute_request);
@@ -484,15 +491,17 @@ static void osd_request_async_done(struct request *req, int error)
{
struct osd_request *or = req->end_io_data;
- or->async_error = error;
-
- if (unlikely(error)) {
- OSD_DEBUG("osd_request_async_done error recieved %d "
- "errors 0x%x\n", error, req->errors);
- if (!req->errors) /* don't miss out on this one */
- req->errors = error;
+ _set_error_resid(or, req, error);
+ if (req->next_rq) {
+ __blk_put_request(req->q, req->next_rq);
+ req->next_rq = NULL;
}
+ __blk_put_request(req->q, req);
+ or->request = NULL;
+ or->in.req = NULL;
+ or->out.req = NULL;
+
if (or->async_done)
or->async_done(or, or->async_private);
else
@@ -1489,21 +1498,18 @@ int osd_req_decode_sense_full(struct osd_request *or,
#endif
int ret;
- if (likely(!or->request->errors)) {
- osi->out_resid = 0;
- osi->in_resid = 0;
+ if (likely(!or->req_errors))
return 0;
- }
osi = osi ? : &local_osi;
memset(osi, 0, sizeof(*osi));
- ssdb = or->request->sense;
- sense_len = or->request->sense_len;
+ ssdb = (typeof(ssdb))or->sense;
+ sense_len = or->sense_len;
if ((sense_len < (int)sizeof(*ssdb) || !ssdb->sense_key)) {
OSD_ERR("Block-layer returned error(0x%x) but "
"sense_len(%u) || key(%d) is empty\n",
- or->request->errors, sense_len, ssdb->sense_key);
+ or->req_errors, sense_len, ssdb->sense_key);
goto analyze;
}
@@ -1525,7 +1531,7 @@ int osd_req_decode_sense_full(struct osd_request *or,
"additional_code=0x%x async_error=%d errors=0x%x\n",
osi->key, original_sense_len, sense_len,
osi->additional_code, or->async_error,
- or->request->errors);
+ or->req_errors);
if (original_sense_len < sense_len)
sense_len = original_sense_len;
@@ -1695,10 +1701,10 @@ analyze:
ret = -EIO;
}
- if (or->out.req)
- osi->out_resid = or->out.req->resid_len ?: or->out.total_bytes;
- if (or->in.req)
- osi->in_resid = or->in.req->resid_len ?: or->in.total_bytes;
+ if (!or->out.residual)
+ or->out.residual = or->out.total_bytes;
+ if (!or->in.residual)
+ or->in.residual = or->in.total_bytes;
return ret;
}