Commit a492f075 authored by Joe Lawrence's avatar Joe Lawrence Committed by Jens Axboe

block,scsi: fixup blk_get_request dead queue scenarios

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: 's avatarJoe 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: 's avatarJeff Moyer <jmoyer@redhat.com>
Signed-off-by: 's avatarJens Axboe <axboe@fb.com>
parent eb571eea
......@@ -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;
}
......
......@@ -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);
......
......@@ -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;
......
......@@ -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;
......
......@@ -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;
......
......@@ -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) {
......
......@@ -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);
......
......@@ -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);
......
......@@ -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;
......
......@@ -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;
......
......@@ -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;
}
......
......@@ -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);
......
......@@ -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;
......
......@@ -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;
......
......@@ -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);
......
......@@ -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);
......
......@@ -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);
......
......@@ -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);
......
......@@ -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);
......
......@@ -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;
......
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