Linux 4.14.111

[thirdparty/kernel/stable-queue.git] / releases / 4.14.111 / scsi-core-replace-gfp_atomic-with-gfp_kernel-in-scsi.patch

diff --git a/releases/4.14.111/scsi-core-replace-gfp_atomic-with-gfp_kernel-in-scsi.patch b/releases/4.14.111/scsi-core-replace-gfp_atomic-with-gfp_kernel-in-scsi.patch
new file mode 100644 (file)
index 0000000..439564a
--- /dev/null
+++ b/releases/4.14.111/scsi-core-replace-gfp_atomic-with-gfp_kernel-in-scsi.patch
@@ -0,0 +1,114 @@
+From 7519cc3bd3213f285c0cde40a0694210666531db Mon Sep 17 00:00:00 2001
+From: Benjamin Block <bblock@linux.ibm.com>
+Date: Thu, 21 Feb 2019 10:18:00 +0100
+Subject: scsi: core: replace GFP_ATOMIC with GFP_KERNEL in scsi_scan.c
+
+[ 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 40124648a07b..0b11405bfd7e 100644
+--- a/drivers/scsi/scsi_scan.c
++++ b/drivers/scsi/scsi_scan.c
+@@ -220,7 +220,7 @@ 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;
+ 
+@@ -1085,7 +1085,7 @@ 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;
+-- 
+2.19.1
+