lwn.git/kernel/workqueue.c, branch docs-4.19

treewide: kzalloc() -> kcalloc()

2018-06-12T23:19:22+00:00

The kzalloc() function has a 2-factor argument form, kcalloc(). This patch replaces cases of: kzalloc(a * b, gfp) with: kcalloc(a * b, gfp) as well as handling cases of: kzalloc(a * b * c, gfp) with: kzalloc(array3_size(a, b, c), gfp) as it's slightly less ugly than: kzalloc_array(array_size(a, b), c, gfp) This does, however, attempt to ignore constant size factors like: kzalloc(4 * 1024, gfp) though any constants defined via macros get caught up in the conversion. Any factors with a sizeof() of "unsigned char", "char", and "u8" were dropped, since they're redundant. The Coccinelle script used for this was: // Fix redundant parens around sizeof(). @@ type TYPE; expression THING, E; @@ ( kzalloc( - (sizeof(TYPE)) * E + sizeof(TYPE) * E , ...) | kzalloc( - (sizeof(THING)) * E + sizeof(THING) * E , ...) ) // Drop single-byte sizes and redundant parens. @@ expression COUNT; typedef u8; typedef __u8; @@ ( kzalloc( - sizeof(u8) * (COUNT) + COUNT , ...) | kzalloc( - sizeof(__u8) * (COUNT) + COUNT , ...) | kzalloc( - sizeof(char) * (COUNT) + COUNT , ...) | kzalloc( - sizeof(unsigned char) * (COUNT) + COUNT , ...) | kzalloc( - sizeof(u8) * COUNT + COUNT , ...) | kzalloc( - sizeof(__u8) * COUNT + COUNT , ...) | kzalloc( - sizeof(char) * COUNT + COUNT , ...) | kzalloc( - sizeof(unsigned char) * COUNT + COUNT , ...) ) // 2-factor product with sizeof(type/expression) and identifier or constant. @@ type TYPE; expression THING; identifier COUNT_ID; constant COUNT_CONST; @@ ( - kzalloc + kcalloc ( - sizeof(TYPE) * (COUNT_ID) + COUNT_ID, sizeof(TYPE) , ...) | - kzalloc + kcalloc ( - sizeof(TYPE) * COUNT_ID + COUNT_ID, sizeof(TYPE) , ...) | - kzalloc + kcalloc ( - sizeof(TYPE) * (COUNT_CONST) + COUNT_CONST, sizeof(TYPE) , ...) | - kzalloc + kcalloc ( - sizeof(TYPE) * COUNT_CONST + COUNT_CONST, sizeof(TYPE) , ...) | - kzalloc + kcalloc ( - sizeof(THING) * (COUNT_ID) + COUNT_ID, sizeof(THING) , ...) | - kzalloc + kcalloc ( - sizeof(THING) * COUNT_ID + COUNT_ID, sizeof(THING) , ...) | - kzalloc + kcalloc ( - sizeof(THING) * (COUNT_CONST) + COUNT_CONST, sizeof(THING) , ...) | - kzalloc + kcalloc ( - sizeof(THING) * COUNT_CONST + COUNT_CONST, sizeof(THING) , ...) ) // 2-factor product, only identifiers. @@ identifier SIZE, COUNT; @@ - kzalloc + kcalloc ( - SIZE * COUNT + COUNT, SIZE , ...) // 3-factor product with 1 sizeof(type) or sizeof(expression), with // redundant parens removed. @@ expression THING; identifier STRIDE, COUNT; type TYPE; @@ ( kzalloc( - sizeof(TYPE) * (COUNT) * (STRIDE) + array3_size(COUNT, STRIDE, sizeof(TYPE)) , ...) | kzalloc( - sizeof(TYPE) * (COUNT) * STRIDE + array3_size(COUNT, STRIDE, sizeof(TYPE)) , ...) | kzalloc( - sizeof(TYPE) * COUNT * (STRIDE) + array3_size(COUNT, STRIDE, sizeof(TYPE)) , ...) | kzalloc( - sizeof(TYPE) * COUNT * STRIDE + array3_size(COUNT, STRIDE, sizeof(TYPE)) , ...) | kzalloc( - sizeof(THING) * (COUNT) * (STRIDE) + array3_size(COUNT, STRIDE, sizeof(THING)) , ...) | kzalloc( - sizeof(THING) * (COUNT) * STRIDE + array3_size(COUNT, STRIDE, sizeof(THING)) , ...) | kzalloc( - sizeof(THING) * COUNT * (STRIDE) + array3_size(COUNT, STRIDE, sizeof(THING)) , ...) | kzalloc( - sizeof(THING) * COUNT * STRIDE + array3_size(COUNT, STRIDE, sizeof(THING)) , ...) ) // 3-factor product with 2 sizeof(variable), with redundant parens removed. @@ expression THING1, THING2; identifier COUNT; type TYPE1, TYPE2; @@ ( kzalloc( - sizeof(TYPE1) * sizeof(TYPE2) * COUNT + array3_size(COUNT, sizeof(TYPE1), sizeof(TYPE2)) , ...) | kzalloc( - sizeof(TYPE1) * sizeof(THING2) * (COUNT) + array3_size(COUNT, sizeof(TYPE1), sizeof(TYPE2)) , ...) | kzalloc( - sizeof(THING1) * sizeof(THING2) * COUNT + array3_size(COUNT, sizeof(THING1), sizeof(THING2)) , ...) | kzalloc( - sizeof(THING1) * sizeof(THING2) * (COUNT) + array3_size(COUNT, sizeof(THING1), sizeof(THING2)) , ...) | kzalloc( - sizeof(TYPE1) * sizeof(THING2) * COUNT + array3_size(COUNT, sizeof(TYPE1), sizeof(THING2)) , ...) | kzalloc( - sizeof(TYPE1) * sizeof(THING2) * (COUNT) + array3_size(COUNT, sizeof(TYPE1), sizeof(THING2)) , ...) ) // 3-factor product, only identifiers, with redundant parens removed. @@ identifier STRIDE, SIZE, COUNT; @@ ( kzalloc( - (COUNT) * STRIDE * SIZE + array3_size(COUNT, STRIDE, SIZE) , ...) | kzalloc( - COUNT * (STRIDE) * SIZE + array3_size(COUNT, STRIDE, SIZE) , ...) | kzalloc( - COUNT * STRIDE * (SIZE) + array3_size(COUNT, STRIDE, SIZE) , ...) | kzalloc( - (COUNT) * (STRIDE) * SIZE + array3_size(COUNT, STRIDE, SIZE) , ...) | kzalloc( - COUNT * (STRIDE) * (SIZE) + array3_size(COUNT, STRIDE, SIZE) , ...) | kzalloc( - (COUNT) * STRIDE * (SIZE) + array3_size(COUNT, STRIDE, SIZE) , ...) | kzalloc( - (COUNT) * (STRIDE) * (SIZE) + array3_size(COUNT, STRIDE, SIZE) , ...) | kzalloc( - COUNT * STRIDE * SIZE + array3_size(COUNT, STRIDE, SIZE) , ...) ) // Any remaining multi-factor products, first at least 3-factor products, // when they're not all constants... @@ expression E1, E2, E3; constant C1, C2, C3; @@ ( kzalloc(C1 * C2 * C3, ...) | kzalloc( - (E1) * E2 * E3 + array3_size(E1, E2, E3) , ...) | kzalloc( - (E1) * (E2) * E3 + array3_size(E1, E2, E3) , ...) | kzalloc( - (E1) * (E2) * (E3) + array3_size(E1, E2, E3) , ...) | kzalloc( - E1 * E2 * E3 + array3_size(E1, E2, E3) , ...) ) // And then all remaining 2 factors products when they're not all constants, // keeping sizeof() as the second factor argument. @@ expression THING, E1, E2; type TYPE; constant C1, C2, C3; @@ ( kzalloc(sizeof(THING) * C2, ...) | kzalloc(sizeof(TYPE) * C2, ...) | kzalloc(C1 * C2 * C3, ...) | kzalloc(C1 * C2, ...) | - kzalloc + kcalloc ( - sizeof(TYPE) * (E2) + E2, sizeof(TYPE) , ...) | - kzalloc + kcalloc ( - sizeof(TYPE) * E2 + E2, sizeof(TYPE) , ...) | - kzalloc + kcalloc ( - sizeof(THING) * (E2) + E2, sizeof(THING) , ...) | - kzalloc + kcalloc ( - sizeof(THING) * E2 + E2, sizeof(THING) , ...) | - kzalloc + kcalloc ( - (E1) * E2 + E1, E2 , ...) | - kzalloc + kcalloc ( - (E1) * (E2) + E1, E2 , ...) | - kzalloc + kcalloc ( - E1 * E2 + E1, E2 , ...) ) Signed-off-by: Kees Cook

Merge tag 'scsi-misc' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi

2018-06-10T20:01:12+00:00

Pull SCSI updates from James Bottomley: "This is mostly updates to the usual drivers: ufs, qedf, mpt3sas, lpfc, xfcp, hisi_sas, cxlflash, qla2xxx. In the absence of Nic, we're also taking target updates which are mostly minor except for the tcmu refactor. The only real core change to worry about is the removal of high page bouncing (in sas, storvsc and iscsi). This has been well tested and no problems have shown up so far" * tag 'scsi-misc' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi: (268 commits) scsi: lpfc: update driver version to 12.0.0.4 scsi: lpfc: Fix port initialization failure. scsi: lpfc: Fix 16gb hbas failing cq create. scsi: lpfc: Fix crash in blk_mq layer when executing modprobe -r lpfc scsi: lpfc: correct oversubscription of nvme io requests for an adapter scsi: lpfc: Fix MDS diagnostics failure (Rx < Tx) scsi: hisi_sas: Mark PHY as in reset for nexus reset scsi: hisi_sas: Fix return value when get_free_slot() failed scsi: hisi_sas: Terminate STP reject quickly for v2 hw scsi: hisi_sas: Add v2 hw force PHY function for internal ATA command scsi: hisi_sas: Include TMF elements in struct hisi_sas_slot scsi: hisi_sas: Try wait commands before before controller reset scsi: hisi_sas: Init disks after controller reset scsi: hisi_sas: Create a scsi_host_template per HW module scsi: hisi_sas: Reset disks when discovered scsi: hisi_sas: Add LED feature for v3 hw scsi: hisi_sas: Change common allocation mode of device id scsi: hisi_sas: change slot index allocation mode scsi: hisi_sas: Introduce hisi_sas_phy_set_linkrate() scsi: hisi_sas: fix a typo in hisi_sas_task_prep() ...

Merge tag 'overflow-v4.18-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux

2018-06-07T00:27:14+00:00

Pull overflow updates from Kees Cook: "This adds the new overflow checking helpers and adds them to the 2-factor argument allocators. And this adds the saturating size helpers and does a treewide replacement for the struct_size() usage. Additionally this adds the overflow testing modules to make sure everything works. I'm still working on the treewide replacements for allocators with "simple" multiplied arguments: *alloc(a * b, ...) -> *alloc_array(a, b, ...) and *zalloc(a * b, ...) -> *calloc(a, b, ...) as well as the more complex cases, but that's separable from this portion of the series. I expect to have the rest sent before -rc1 closes; there are a lot of messy cases to clean up. Summary: - Introduce arithmetic overflow test helper functions (Rasmus) - Use overflow helpers in 2-factor allocators (Kees, Rasmus) - Introduce overflow test module (Rasmus, Kees) - Introduce saturating size helper functions (Matthew, Kees) - Treewide use of struct_size() for allocators (Kees)" * tag 'overflow-v4.18-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux: treewide: Use struct_size() for devm_kmalloc() and friends treewide: Use struct_size() for vmalloc()-family treewide: Use struct_size() for kmalloc()-family device: Use overflow helpers for devm_kmalloc() mm: Use overflow helpers in kvmalloc() mm: Use overflow helpers in kmalloc_array*() test_overflow: Add memory allocation overflow tests overflow.h: Add allocation size calculation helpers test_overflow: Report test failures test_overflow: macrofy some more, do more tests for free lib: add runtime test of check_*_overflow functions compiler.h: enable builtin overflow checkers and add fallback code

treewide: Use struct_size() for kmalloc()-family

2018-06-06T18:15:43+00:00

One of the more common cases of allocation size calculations is finding the size of a structure that has a zero-sized array at the end, along with memory for some number of elements for that array. For example: struct foo { int stuff; void *entry[]; }; instance = kmalloc(sizeof(struct foo) + sizeof(void *) * count, GFP_KERNEL); Instead of leaving these open-coded and prone to type mistakes, we can now use the new struct_size() helper: instance = kmalloc(struct_size(instance, entry, count), GFP_KERNEL); This patch makes the changes for kmalloc()-family (and kvmalloc()-family) uses. It was done via automatic conversion with manual review for the "CHECKME" non-standard cases noted below, using the following Coccinelle script: // pkey_cache = kmalloc(sizeof *pkey_cache + tprops->pkey_tbl_len * // sizeof *pkey_cache->table, GFP_KERNEL); @@ identifier alloc =~ "kmalloc|kzalloc|kvmalloc|kvzalloc"; expression GFP; identifier VAR, ELEMENT; expression COUNT; @@ - alloc(sizeof(*VAR) + COUNT * sizeof(*VAR->ELEMENT), GFP) + alloc(struct_size(VAR, ELEMENT, COUNT), GFP) // mr = kzalloc(sizeof(*mr) + m * sizeof(mr->map[0]), GFP_KERNEL); @@ identifier alloc =~ "kmalloc|kzalloc|kvmalloc|kvzalloc"; expression GFP; identifier VAR, ELEMENT; expression COUNT; @@ - alloc(sizeof(*VAR) + COUNT * sizeof(VAR->ELEMENT[0]), GFP) + alloc(struct_size(VAR, ELEMENT, COUNT), GFP) // Same pattern, but can't trivially locate the trailing element name, // or variable name. @@ identifier alloc =~ "kmalloc|kzalloc|kvmalloc|kvzalloc"; expression GFP; expression SOMETHING, COUNT, ELEMENT; @@ - alloc(sizeof(SOMETHING) + COUNT * sizeof(ELEMENT), GFP) + alloc(CHECKME_struct_size(&SOMETHING, ELEMENT, COUNT), GFP) Signed-off-by: Kees Cook

workqueue: move function definitions within CONFIG_SMP block

2018-05-23T18:16:58+00:00

In commit 7ee681b25284 ("workqueue: Convert to state machine callbacks"), three new function definitions were added: ‘workqueue_prepare_cpu’, ‘workqueue_online_cpu’ and ‘workqueue_offline_cpu’. Move these function definitions within a CONFIG_SMP block since they are not used outside of it. This will match function declarations in header , and silence the following gcc warning (W=1): kernel/workqueue.c:4743:5: warning: no previous prototype for ‘workqueue_prepare_cpu’ [-Wmissing-prototypes] kernel/workqueue.c:4756:5: warning: no previous prototype for ‘workqueue_online_cpu’ [-Wmissing-prototypes] kernel/workqueue.c:4783:5: warning: no previous prototype for ‘workqueue_offline_cpu’ [-Wmissing-prototypes] Signed-off-by: Mathieu Malaterre Signed-off-by: Tejun Heo

workqueue: Make sure struct worker is accessible for wq_worker_comm()

2018-05-21T15:04:35+00:00

The worker struct could already be freed when wq_worker_comm() tries to access it for reporting. This patch protects PF_WQ_WORKER modifications with wq_pool_attach_mutex and makes wq_worker_comm() test the flag before dereferencing worker from kthread_data(), which ensures that it only dereferences when the worker struct is valid. Signed-off-by: Tejun Heo Reported-by: Lai Jiangshan Fixes: 6b59808bfe48 ("workqueue: Show the latest workqueue name in /proc/PID/{comm,stat,status}")

workqueue: Show the latest workqueue name in /proc/PID/{comm,stat,status}

2018-05-18T15:47:13+00:00

There can be a lot of workqueue workers and they all show up with the cryptic kworker/* names making it difficult to understand which is doing what and how they came to be. # ps -ef | grep kworker root 4 2 0 Feb25 ? 00:00:00 [kworker/0:0H] root 6 2 0 Feb25 ? 00:00:00 [kworker/u112:0] root 19 2 0 Feb25 ? 00:00:00 [kworker/1:0H] root 25 2 0 Feb25 ? 00:00:00 [kworker/2:0H] root 31 2 0 Feb25 ? 00:00:00 [kworker/3:0H] ... This patch makes workqueue workers report the latest workqueue it was executing for through /proc/PID/{comm,stat,status}. The extra information is appended to the kthread name with intervening '+' if currently executing, otherwise '-'. # cat /proc/25/comm kworker/2:0-events_power_efficient # cat /proc/25/stat 25 (kworker/2:0-events_power_efficient) I 2 0 0 0 -1 69238880 0 0... # grep Name /proc/25/status Name: kworker/2:0-events_power_efficient Unfortunately, ps(1) truncates comm to 15 characters, # ps 25 PID TTY STAT TIME COMMAND 25 ? I 0:00 [kworker/2:0-eve] making it a lot less useful; however, this should be an easy fix from ps(1) side. Signed-off-by: Tejun Heo Suggested-by: Linus Torvalds Cc: Craig Small

workqueue: Set worker->desc to workqueue name by default

2018-05-18T15:47:13+00:00

Work functions can use set_worker_desc() to improve the visibility of what the worker task is doing. Currently, the desc field is unset at the beginning of each execution and there is a separate field to track the field is set during the current execution. Instead of leaving empty till desc is set, worker->desc can be used to remember the last workqueue the worker worked on by default and users that use set_worker_desc() can override it to something more informative as necessary. This simplifies desc handling and helps tracking the last workqueue that the worker exected on to improve visibility. Signed-off-by: Tejun Heo

workqueue: Make worker_attach/detach_pool() update worker->pool

2018-05-18T15:47:13+00:00

For historical reasons, the worker attach/detach functions don't currently manage worker->pool and the callers are manually and inconsistently updating it. This patch moves worker->pool updates into the worker attach/detach functions. This makes worker->pool consistent and clearly defines how worker->pool updates are synchronized. This will help later workqueue visibility improvements by allowing safe access to workqueue information from worker->task. Signed-off-by: Tejun Heo

workqueue: Replace pool->attach_mutex with global wq_pool_attach_mutex

2018-05-18T15:47:13+00:00

To improve workqueue visibility, we want to be able to access workqueue information from worker tasks. The per-pool attach mutex makes that difficult because there's no way of stabilizing task -> worker pool association without knowing the pool first. Worker attach/detach is a slow path and there's no need for different pools to be able to perform them concurrently. This patch replaces the per-pool attach_mutex with global wq_pool_attach_mutex to prepare for visibility improvement changes. Signed-off-by: Tejun Heo