From: Benjamin Block bblock@linux.ibm.com
[ Upstream commit 1749ef00f7312679f76d5e9104c5d1e22a829038 ]
We had a test-report where, under memory pressure, adding LUNs to the systems would fail (the tests add LUNs strictly in sequence):
[ 5525.853432] scsi 0:0:1:1088045124: Direct-Access IBM 2107900 .148 PQ: 0 ANSI: 5 [ 5525.853826] scsi 0:0:1:1088045124: alua: supports implicit TPGS [ 5525.853830] scsi 0:0:1:1088045124: alua: device naa.6005076303ffd32700000000000044da port group 0 rel port 43 [ 5525.853931] sd 0:0:1:1088045124: Attached scsi generic sg10 type 0 [ 5525.854075] sd 0:0:1:1088045124: [sdk] Disabling DIF Type 1 protection [ 5525.855495] sd 0:0:1:1088045124: [sdk] 2097152 512-byte logical blocks: (1.07 GB/1.00 GiB) [ 5525.855606] sd 0:0:1:1088045124: [sdk] Write Protect is off [ 5525.855609] sd 0:0:1:1088045124: [sdk] Mode Sense: ed 00 00 08 [ 5525.855795] sd 0:0:1:1088045124: [sdk] Write cache: enabled, read cache: enabled, doesn't support DPO or FUA [ 5525.857838] sdk: sdk1 [ 5525.859468] sd 0:0:1:1088045124: [sdk] Attached SCSI disk [ 5525.865073] sd 0:0:1:1088045124: alua: transition timeout set to 60 seconds [ 5525.865078] sd 0:0:1:1088045124: alua: port group 00 state A preferred supports tolusnA [ 5526.015070] sd 0:0:1:1088045124: alua: port group 00 state A preferred supports tolusnA [ 5526.015213] sd 0:0:1:1088045124: alua: port group 00 state A preferred supports tolusnA [ 5526.587439] scsi_alloc_sdev: Allocation failure during SCSI scanning, some SCSI devices might not be configured [ 5526.588562] scsi_alloc_sdev: Allocation failure during SCSI scanning, some SCSI devices might not be configured
Looking at the code of scsi_alloc_sdev(), and all the calling contexts, there seems to be no reason to use GFP_ATMOIC here. All the different call-contexts use a mutex at some point, and nothing in between that requires no sleeping, as far as I could see. Additionally, the code that later allocates the block queue for the device (scsi_mq_alloc_queue()) already uses GFP_KERNEL.
There are similar allocations in two other functions: scsi_probe_and_add_lun(), and scsi_add_lun(),; that can also be done with GFP_KERNEL.
Here is the contexts for the three functions so far:
scsi_alloc_sdev() scsi_probe_and_add_lun() scsi_sequential_lun_scan() __scsi_scan_target() scsi_scan_target() mutex_lock() scsi_scan_channel() scsi_scan_host_selected() mutex_lock() scsi_report_lun_scan() __scsi_scan_target() ... __scsi_add_device() mutex_lock() __scsi_scan_target() ... scsi_report_lun_scan() ... scsi_get_host_dev() mutex_lock()
scsi_probe_and_add_lun() ...
scsi_add_lun() scsi_probe_and_add_lun() ...
So replace all these, and give them a bit of a better chance to succeed, with more chances of reclaim.
Signed-off-by: Benjamin Block bblock@linux.ibm.com Reviewed-by: Bart Van Assche bvanassche@acm.org Signed-off-by: Martin K. Petersen martin.petersen@oracle.com Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/scsi/scsi_scan.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/drivers/scsi/scsi_scan.c b/drivers/scsi/scsi_scan.c index 27a6d3c6cb7c..67f6f134abc4 100644 --- a/drivers/scsi/scsi_scan.c +++ b/drivers/scsi/scsi_scan.c @@ -219,7 +219,7 @@ static struct scsi_device *scsi_alloc_sdev(struct scsi_target *starget, struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
sdev = kzalloc(sizeof(*sdev) + shost->transportt->device_size, - GFP_ATOMIC); + GFP_KERNEL); if (!sdev) goto out;
@@ -796,7 +796,7 @@ static int scsi_add_lun(struct scsi_device *sdev, unsigned char *inq_result, */ sdev->inquiry = kmemdup(inq_result, max_t(size_t, sdev->inquiry_len, 36), - GFP_ATOMIC); + GFP_KERNEL); if (sdev->inquiry == NULL) return SCSI_SCAN_NO_RESPONSE;
@@ -1095,7 +1095,7 @@ static int scsi_probe_and_add_lun(struct scsi_target *starget, if (!sdev) goto out;
- result = kmalloc(result_len, GFP_ATOMIC | + result = kmalloc(result_len, GFP_KERNEL | ((shost->unchecked_isa_dma) ? __GFP_DMA : 0)); if (!result) goto out_free_sdev;