From 40d84e198b0ae64df71ac0e70675b16900b90bde Mon Sep 17 00:00:00 2001 From: Chen Yu Date: Wed, 6 Sep 2023 12:18:41 +0800 Subject: [PATCH 1/2] PM: hibernate: Rename function parameter from snapshot_test to exclusive Several functions reply on snapshot_test to decide whether to open the resume device exclusively. However there is no strict connection between the snapshot_test and the open mode. Rename the 'snapshot_test' input parameter to 'exclusive' to better reflect the use case. No functional change is expected. Signed-off-by: Chen Yu Signed-off-by: Rafael J. Wysocki --- kernel/power/power.h | 4 ++-- kernel/power/swap.c | 14 ++++++++------ 2 files changed, 10 insertions(+), 8 deletions(-) diff --git a/kernel/power/power.h b/kernel/power/power.h index 46eb14dc50c3..a98f95e309a3 100644 --- a/kernel/power/power.h +++ b/kernel/power/power.h @@ -168,11 +168,11 @@ extern int swsusp_swap_in_use(void); #define SF_HW_SIG 8 /* kernel/power/hibernate.c */ -int swsusp_check(bool snapshot_test); +int swsusp_check(bool exclusive); extern void swsusp_free(void); extern int swsusp_read(unsigned int *flags_p); extern int swsusp_write(unsigned int flags); -void swsusp_close(bool snapshot_test); +void swsusp_close(bool exclusive); #ifdef CONFIG_SUSPEND extern int swsusp_unmark(void); #endif diff --git a/kernel/power/swap.c b/kernel/power/swap.c index f6ebcd00c410..74edbce2320b 100644 --- a/kernel/power/swap.c +++ b/kernel/power/swap.c @@ -1513,12 +1513,13 @@ end: static void *swsusp_holder; /** - * swsusp_check - Check for swsusp signature in the resume device + * swsusp_check - Check for swsusp signature in the resume device + * @exclusive: Open the resume device exclusively. */ -int swsusp_check(bool snapshot_test) +int swsusp_check(bool exclusive) { - void *holder = snapshot_test ? &swsusp_holder : NULL; + void *holder = exclusive ? &swsusp_holder : NULL; int error; hib_resume_bdev = blkdev_get_by_dev(swsusp_resume_device, BLK_OPEN_READ, @@ -1563,17 +1564,18 @@ put: } /** - * swsusp_close - close swap device. + * swsusp_close - close swap device. + * @exclusive: Close the resume device which is exclusively opened. */ -void swsusp_close(bool snapshot_test) +void swsusp_close(bool exclusive) { if (IS_ERR(hib_resume_bdev)) { pr_debug("Image device not initialised\n"); return; } - blkdev_put(hib_resume_bdev, snapshot_test ? &swsusp_holder : NULL); + blkdev_put(hib_resume_bdev, exclusive ? &swsusp_holder : NULL); } /** From 148b6f4cc3920e563094540fe1a12d00d3bbccae Mon Sep 17 00:00:00 2001 From: Chen Yu Date: Wed, 6 Sep 2023 12:18:52 +0800 Subject: [PATCH 2/2] PM: hibernate: Fix the exclusive get block device in test_resume mode Commit 5904de0d735b ("PM: hibernate: Do not get block device exclusively in test_resume mode") fixes a hibernation issue under test_resume mode. That commit is supposed to open the block device in non-exclusive mode when in test_resume. However the code does the opposite, which is against its description. In summary, the swap device is only opened exclusively by swsusp_check() with its corresponding *close(), and must be in non test_resume mode. This is to avoid the race condition that different processes scribble the device at the same time. All the other cases should use non-exclusive mode. Fix it by really disabling exclusive mode under test_resume. Fixes: 5904de0d735b ("PM: hibernate: Do not get block device exclusively in test_resume mode") Closes: https://lore.kernel.org/lkml/000000000000761f5f0603324129@google.com/ Reported-by: Pengfei Xu Signed-off-by: Chen Yu Tested-by: Chenzhou Feng Signed-off-by: Rafael J. Wysocki --- kernel/power/hibernate.c | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) diff --git a/kernel/power/hibernate.c b/kernel/power/hibernate.c index 2b4a946a6ff5..8d35b9f9aaa3 100644 --- a/kernel/power/hibernate.c +++ b/kernel/power/hibernate.c @@ -786,9 +786,9 @@ int hibernate(void) unlock_device_hotplug(); if (snapshot_test) { pm_pr_dbg("Checking hibernation image\n"); - error = swsusp_check(snapshot_test); + error = swsusp_check(false); if (!error) - error = load_image_and_restore(snapshot_test); + error = load_image_and_restore(false); } thaw_processes(); @@ -945,14 +945,14 @@ static int software_resume(void) pm_pr_dbg("Looking for hibernation image.\n"); mutex_lock(&system_transition_mutex); - error = swsusp_check(false); + error = swsusp_check(true); if (error) goto Unlock; /* The snapshot device should not be opened while we're running */ if (!hibernate_acquire()) { error = -EBUSY; - swsusp_close(false); + swsusp_close(true); goto Unlock; } @@ -973,7 +973,7 @@ static int software_resume(void) goto Close_Finish; } - error = load_image_and_restore(false); + error = load_image_and_restore(true); thaw_processes(); Finish: pm_notifier_call_chain(PM_POST_RESTORE); @@ -987,7 +987,7 @@ static int software_resume(void) pm_pr_dbg("Hibernation image not present or could not be loaded.\n"); return error; Close_Finish: - swsusp_close(false); + swsusp_close(true); goto Finish; }