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block,scsi: fixup blk_get_request dead queue scenarios

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The blk_get_request function may fail in low-memory conditions or during
device removal (even if __GFP_WAIT is set). To distinguish between these
errors, modify the blk_get_request call stack to return the appropriate
ERR_PTR. Verify that all callers check the return status and consider
IS_ERR instead of a simple NULL pointer check.

For consistency, make a similar change to the blk_mq_alloc_request leg
of blk_get_request.  It may fail if the queue is dead, or the caller was
unwilling to wait.

Signed-off-by: Joe Lawrence <joe.lawrence@stratus.com>
Acked-by: Jiri Kosina <jkosina@suse.cz> [for pktdvd]
Acked-by: Boaz Harrosh <bharrosh@panasas.com> [for osd]
Reviewed-by: Jeff Moyer <jmoyer@redhat.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
This commit is contained in:
Joe Lawrence 2014-08-28 08:15:21 -06:00 committed by Jens Axboe
parent eb571eeade
commit a492f07545
20 changed files with 55 additions and 51 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

34
block/blk-core.c
View File

@ -933,9 +933,9 @@ static struct io_context *rq_ioc(struct bio *bio)
* Get a free request from @q. This function may fail under memory
* pressure or if @q is dead.
*
* Must be callled with @q->queue_lock held and,
* Returns %NULL on failure, with @q->queue_lock held.
* Returns !%NULL on success, with @q->queue_lock *not held*.
* Must be called with @q->queue_lock held and,
* Returns ERR_PTR on failure, with @q->queue_lock held.
* Returns request pointer on success, with @q->queue_lock *not held*.
*/
static struct request *__get_request(struct request_list *rl, int rw_flags,
struct bio *bio, gfp_t gfp_mask)
@ -949,7 +949,7 @@ static struct request *__get_request(struct request_list *rl, int rw_flags,
int may_queue;
if (unlikely(blk_queue_dying(q)))
return NULL;
return ERR_PTR(-ENODEV);
may_queue = elv_may_queue(q, rw_flags);
if (may_queue == ELV_MQUEUE_NO)
@ -974,7 +974,7 @@ static struct request *__get_request(struct request_list *rl, int rw_flags,
* process is not a "batcher", and not
* exempted by the IO scheduler
*/
return NULL;
return ERR_PTR(-ENOMEM);
}
}
}
@ -992,7 +992,7 @@ static struct request *__get_request(struct request_list *rl, int rw_flags,
* allocated with any setting of ->nr_requests
*/
if (rl->count[is_sync] >= (3 * q->nr_requests / 2))
return NULL;
return ERR_PTR(-ENOMEM);
q->nr_rqs[is_sync]++;
rl->count[is_sync]++;
@ -1097,7 +1097,7 @@ fail_alloc:
rq_starved:
if (unlikely(rl->count[is_sync] == 0))
rl->starved[is_sync] = 1;
return NULL;
return ERR_PTR(-ENOMEM);
}
/**
@ -1110,9 +1110,9 @@ rq_starved:
* Get a free request from @q. If %__GFP_WAIT is set in @gfp_mask, this
* function keeps retrying under memory pressure and fails iff @q is dead.
*
* Must be callled with @q->queue_lock held and,
* Returns %NULL on failure, with @q->queue_lock held.
* Returns !%NULL on success, with @q->queue_lock *not held*.
* Must be called with @q->queue_lock held and,
* Returns ERR_PTR on failure, with @q->queue_lock held.
* Returns request pointer on success, with @q->queue_lock *not held*.
*/
static struct request *get_request(struct request_queue *q, int rw_flags,
struct bio *bio, gfp_t gfp_mask)
@ -1125,12 +1125,12 @@ static struct request *get_request(struct request_queue *q, int rw_flags,
rl = blk_get_rl(q, bio); /* transferred to @rq on success */
retry:
rq = __get_request(rl, rw_flags, bio, gfp_mask);
if (rq)
if (!IS_ERR(rq))
return rq;
if (!(gfp_mask & __GFP_WAIT) || unlikely(blk_queue_dying(q))) {
blk_put_rl(rl);
return NULL;
return rq;
}
/* wait on @rl and retry */
@ -1167,7 +1167,7 @@ static struct request *blk_old_get_request(struct request_queue *q, int rw,
spin_lock_irq(q->queue_lock);
rq = get_request(q, rw, NULL, gfp_mask);
if (!rq)
if (IS_ERR(rq))
spin_unlock_irq(q->queue_lock);
/* q->queue_lock is unlocked at this point */
@ -1219,8 +1219,8 @@ struct request *blk_make_request(struct request_queue *q, struct bio *bio,
{
struct request *rq = blk_get_request(q, bio_data_dir(bio), gfp_mask);
if (unlikely(!rq))
return ERR_PTR(-ENOMEM);
if (IS_ERR(rq))
return rq;
blk_rq_set_block_pc(rq);
@ -1615,8 +1615,8 @@ get_rq:
* Returns with the queue unlocked.
*/
req = get_request(q, rw_flags, bio, GFP_NOIO);
if (unlikely(!req)) {
bio_endio(bio, -ENODEV); /* @q is dead */
if (IS_ERR(req)) {
bio_endio(bio, PTR_ERR(req)); /* @q is dead */
goto out_unlock;
}

8
block/blk-mq.c
View File

@ -218,9 +218,11 @@ struct request *blk_mq_alloc_request(struct request_queue *q, int rw, gfp_t gfp,
struct blk_mq_hw_ctx *hctx;
struct request *rq;
struct blk_mq_alloc_data alloc_data;
int ret;
if (blk_mq_queue_enter(q))
return NULL;
ret = blk_mq_queue_enter(q);
if (ret)
return ERR_PTR(ret);
ctx = blk_mq_get_ctx(q);
hctx = q->mq_ops->map_queue(q, ctx->cpu);
@ -240,6 +242,8 @@ struct request *blk_mq_alloc_request(struct request_queue *q, int rw, gfp_t gfp,
ctx = alloc_data.ctx;
}
blk_mq_put_ctx(ctx);
if (!rq)
return ERR_PTR(-EWOULDBLOCK);
return rq;
}
EXPORT_SYMBOL(blk_mq_alloc_request);

8
block/bsg.c
View File

@ -270,8 +270,8 @@ bsg_map_hdr(struct bsg_device *bd, struct sg_io_v4 *hdr, fmode_t has_write_perm,
* map scatter-gather elements separately and string them to request
*/
rq = blk_get_request(q, rw, GFP_KERNEL);
if (!rq)
return ERR_PTR(-ENOMEM);
if (IS_ERR(rq))
return rq;
blk_rq_set_block_pc(rq);
ret = blk_fill_sgv4_hdr_rq(q, rq, hdr, bd, has_write_perm);
@ -285,8 +285,8 @@ bsg_map_hdr(struct bsg_device *bd, struct sg_io_v4 *hdr, fmode_t has_write_perm,
}
next_rq = blk_get_request(q, READ, GFP_KERNEL);
if (!next_rq) {
ret = -ENOMEM;
if (IS_ERR(next_rq)) {
ret = PTR_ERR(next_rq);
goto out;
}
rq->next_rq = next_rq;

12
block/scsi_ioctl.c
View File

@ -318,8 +318,8 @@ static int sg_io(struct request_queue *q, struct gendisk *bd_disk,
at_head = 1;
rq = blk_get_request(q, writing ? WRITE : READ, GFP_KERNEL);
if (!rq)
return -ENOMEM;
if (IS_ERR(rq))
return PTR_ERR(rq);
blk_rq_set_block_pc(rq);
if (blk_fill_sghdr_rq(q, rq, hdr, mode)) {
@ -448,8 +448,8 @@ int sg_scsi_ioctl(struct request_queue *q, struct gendisk *disk, fmode_t mode,
}
rq = blk_get_request(q, in_len ? WRITE : READ, __GFP_WAIT);
if (!rq) {
err = -ENODEV;
if (IS_ERR(rq)) {
err = PTR_ERR(rq);
goto error_free_buffer;
}
@ -539,8 +539,8 @@ static int __blk_send_generic(struct request_queue *q, struct gendisk *bd_disk,
int err;
rq = blk_get_request(q, WRITE, __GFP_WAIT);
if (!rq)
return -ENODEV;
if (IS_ERR(rq))
return PTR_ERR(rq);
blk_rq_set_block_pc(rq);
rq->timeout = BLK_DEFAULT_SG_TIMEOUT;
rq->cmd[0] = cmd;

4
drivers/block/paride/pd.c
View File

@ -722,8 +722,8 @@ static int pd_special_command(struct pd_unit *disk,
int err = 0;
rq = blk_get_request(disk->gd->queue, READ, __GFP_WAIT);
if (!rq)
return -ENODEV;
if (IS_ERR(rq))
return PTR_ERR(rq);
rq->cmd_type = REQ_TYPE_SPECIAL;
rq->special = func;

4
drivers/block/pktcdvd.c
View File

@ -704,8 +704,8 @@ static int pkt_generic_packet(struct pktcdvd_device *pd, struct packet_command *
rq = blk_get_request(q, (cgc->data_direction == CGC_DATA_WRITE) ?
WRITE : READ, __GFP_WAIT);
if (!rq)
return -ENODEV;
if (IS_ERR(rq))
return PTR_ERR(rq);
blk_rq_set_block_pc(rq);
if (cgc->buflen) {

2
drivers/block/sx8.c
View File

@ -568,7 +568,7 @@ static struct carm_request *carm_get_special(struct carm_host *host)
return NULL;
rq = blk_get_request(host->oob_q, WRITE /* bogus */, GFP_KERNEL);
if (!rq) {
if (IS_ERR(rq)) {
spin_lock_irqsave(&host->lock, flags);
carm_put_request(host, crq);
spin_unlock_irqrestore(&host->lock, flags);

4
drivers/cdrom/cdrom.c
View File

@ -2180,8 +2180,8 @@ static int cdrom_read_cdda_bpc(struct cdrom_device_info *cdi, __u8 __user *ubuf,
len = nr * CD_FRAMESIZE_RAW;
rq = blk_get_request(q, READ, GFP_KERNEL);
if (!rq) {
ret = -ENOMEM;
if (IS_ERR(rq)) {
ret = PTR_ERR(rq);
break;
}
blk_rq_set_block_pc(rq);

2
drivers/ide/ide-park.c
View File

@ -46,7 +46,7 @@ static void issue_park_cmd(ide_drive_t *drive, unsigned long timeout)
* timeout has expired, so power management will be reenabled.
*/
rq = blk_get_request(q, READ, GFP_NOWAIT);
if (unlikely(!rq))
if (IS_ERR(rq))
goto out;
rq->cmd[0] = REQ_UNPARK_HEADS;

2
drivers/scsi/device_handler/scsi_dh_alua.c
View File

@ -115,7 +115,7 @@ static struct request *get_alua_req(struct scsi_device *sdev,
rq = blk_get_request(q, rw, GFP_NOIO);
if (!rq) {
if (IS_ERR(rq)) {
sdev_printk(KERN_INFO, sdev,
"%s: blk_get_request failed\n", __func__);
return NULL;

2
drivers/scsi/device_handler/scsi_dh_emc.c
View File

@ -275,7 +275,7 @@ static struct request *get_req(struct scsi_device *sdev, int cmd,
rq = blk_get_request(sdev->request_queue,
(cmd != INQUIRY) ? WRITE : READ, GFP_NOIO);
if (!rq) {
if (IS_ERR(rq)) {
sdev_printk(KERN_INFO, sdev, "get_req: blk_get_request failed");
return NULL;
}

4
drivers/scsi/device_handler/scsi_dh_hp_sw.c
View File

@ -117,7 +117,7 @@ static int hp_sw_tur(struct scsi_device *sdev, struct hp_sw_dh_data *h)
retry:
req = blk_get_request(sdev->request_queue, WRITE, GFP_NOIO);
if (!req)
if (IS_ERR(req))
return SCSI_DH_RES_TEMP_UNAVAIL;
blk_rq_set_block_pc(req);
@ -247,7 +247,7 @@ static int hp_sw_start_stop(struct hp_sw_dh_data *h)
struct request *req;
req = blk_get_request(h->sdev->request_queue, WRITE, GFP_ATOMIC);
if (!req)
if (IS_ERR(req))
return SCSI_DH_RES_TEMP_UNAVAIL;
blk_rq_set_block_pc(req);

2
drivers/scsi/device_handler/scsi_dh_rdac.c
View File

@ -274,7 +274,7 @@ static struct request *get_rdac_req(struct scsi_device *sdev,
rq = blk_get_request(q, rw, GFP_NOIO);
if (!rq) {
if (IS_ERR(rq)) {
sdev_printk(KERN_INFO, sdev,
"get_rdac_req: blk_get_request failed.\n");
return NULL;

4
drivers/scsi/osd/osd_initiator.c
View File

@ -1567,8 +1567,8 @@ static struct request *_make_request(struct request_queue *q, bool has_write,
struct request *req;
req = blk_get_request(q, has_write ? WRITE : READ, flags);
if (unlikely(!req))
return ERR_PTR(-ENOMEM);
if (IS_ERR(req))
return req;
blk_rq_set_block_pc(req);
return req;

2
drivers/scsi/osst.c
View File

@ -362,7 +362,7 @@ static int osst_execute(struct osst_request *SRpnt, const unsigned char *cmd,
int write = (data_direction == DMA_TO_DEVICE);
req = blk_get_request(SRpnt->stp->device->request_queue, write, GFP_KERNEL);
if (!req)
if (IS_ERR(req))
return DRIVER_ERROR << 24;
blk_rq_set_block_pc(req);

2
drivers/scsi/scsi_error.c
View File

@ -1960,7 +1960,7 @@ static void scsi_eh_lock_door(struct scsi_device *sdev)
* request becomes available
*/
req = blk_get_request(sdev->request_queue, READ, GFP_KERNEL);
if (!req)
if (IS_ERR(req))
return;
blk_rq_set_block_pc(req);

2
drivers/scsi/scsi_lib.c
View File

@ -221,7 +221,7 @@ int scsi_execute(struct scsi_device *sdev, const unsigned char *cmd,
int ret = DRIVER_ERROR << 24;
req = blk_get_request(sdev->request_queue, write, __GFP_WAIT);
if (!req)
if (IS_ERR(req))
return ret;
blk_rq_set_block_pc(req);

4
drivers/scsi/sg.c
View File

@ -1711,9 +1711,9 @@ sg_start_req(Sg_request *srp, unsigned char *cmd)
}
rq = blk_get_request(q, rw, GFP_ATOMIC);
if (!rq) {
if (IS_ERR(rq)) {
kfree(long_cmdp);
return -ENOMEM;
return PTR_ERR(rq);
}
blk_rq_set_block_pc(rq);

2
drivers/scsi/st.c
View File

@ -490,7 +490,7 @@ static int st_scsi_execute(struct st_request *SRpnt, const unsigned char *cmd,
req = blk_get_request(SRpnt->stp->device->request_queue, write,
GFP_KERNEL);
if (!req)
if (IS_ERR(req))
return DRIVER_ERROR << 24;
blk_rq_set_block_pc(req);

2
drivers/target/target_core_pscsi.c
View File

@ -1050,7 +1050,7 @@ pscsi_execute_cmd(struct se_cmd *cmd)
req = blk_get_request(pdv->pdv_sd->request_queue,
(data_direction == DMA_TO_DEVICE),
GFP_KERNEL);
if (!req) {
if (IS_ERR(req)) {
pr_err("PSCSI: blk_get_request() failed\n");
ret = TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
goto fail;