From: Liang Zhen <liang.zhen@xxxxxxxxx> page_collection::pc_lock is supposed to protect race between functions called by smp_call_function(), however we don't have this use-case for ages and page_collection only lives in stack of thread, so it is safe to remove it. Signed-off-by: Liang Zhen <liang.zhen@xxxxxxxxx> Intel-bug-id: https://jira.hpdd.intel.com/browse/LU-3055 Reviewed-on: http://review.whamcloud.com/7660 Reviewed-by: Bobi Jam <bobijam@xxxxxxxxx> Reviewed-by: Sebastien Buisson <sebastien.buisson@xxxxxxxx> Reviewed-by: Oleg Drokin <oleg.drokin@xxxxxxxxx> --- drivers/staging/lustre/lustre/libcfs/tracefile.c | 14 -------------- drivers/staging/lustre/lustre/libcfs/tracefile.h | 8 -------- 2 files changed, 0 insertions(+), 22 deletions(-) diff --git a/drivers/staging/lustre/lustre/libcfs/tracefile.c b/drivers/staging/lustre/lustre/libcfs/tracefile.c index 973c7c2..6fe7dfb 100644 --- a/drivers/staging/lustre/lustre/libcfs/tracefile.c +++ b/drivers/staging/lustre/lustre/libcfs/tracefile.c @@ -199,7 +199,6 @@ static void cfs_tcd_shrink(struct cfs_trace_cpu_data *tcd) pgcount + 1, tcd->tcd_cur_pages); INIT_LIST_HEAD(&pc.pc_pages); - spin_lock_init(&pc.pc_lock); list_for_each_entry_safe(tage, tmp, &tcd->tcd_pages, linkage) { if (pgcount-- == 0) @@ -522,7 +521,6 @@ static void collect_pages_on_all_cpus(struct page_collection *pc) struct cfs_trace_cpu_data *tcd; int i, cpu; - spin_lock(&pc->pc_lock); for_each_possible_cpu(cpu) { cfs_tcd_for_each_type_lock(tcd, i, cpu) { list_splice_init(&tcd->tcd_pages, &pc->pc_pages); @@ -534,7 +532,6 @@ static void collect_pages_on_all_cpus(struct page_collection *pc) } } } - spin_unlock(&pc->pc_lock); } static void collect_pages(struct page_collection *pc) @@ -555,7 +552,6 @@ static void put_pages_back_on_all_cpus(struct page_collection *pc) struct cfs_trace_page *tmp; int i, cpu; - spin_lock(&pc->pc_lock); for_each_possible_cpu(cpu) { cfs_tcd_for_each_type_lock(tcd, i, cpu) { cur_head = tcd->tcd_pages.next; @@ -573,7 +569,6 @@ static void put_pages_back_on_all_cpus(struct page_collection *pc) } } } - spin_unlock(&pc->pc_lock); } static void put_pages_back(struct page_collection *pc) @@ -592,7 +587,6 @@ static void put_pages_on_tcd_daemon_list(struct page_collection *pc, struct cfs_trace_page *tage; struct cfs_trace_page *tmp; - spin_lock(&pc->pc_lock); list_for_each_entry_safe(tage, tmp, &pc->pc_pages, linkage) { __LASSERT_TAGE_INVARIANT(tage); @@ -616,7 +610,6 @@ static void put_pages_on_tcd_daemon_list(struct page_collection *pc, tcd->tcd_cur_daemon_pages--; } } - spin_unlock(&pc->pc_lock); } static void put_pages_on_daemon_list(struct page_collection *pc) @@ -636,8 +629,6 @@ void cfs_trace_debug_print(void) struct cfs_trace_page *tage; struct cfs_trace_page *tmp; - spin_lock_init(&pc.pc_lock); - pc.pc_want_daemon_pages = 1; collect_pages(&pc); list_for_each_entry_safe(tage, tmp, &pc.pc_pages, linkage) { @@ -692,7 +683,6 @@ int cfs_tracefile_dump_all_pages(char *filename) goto out; } - spin_lock_init(&pc.pc_lock); pc.pc_want_daemon_pages = 1; collect_pages(&pc); if (list_empty(&pc.pc_pages)) { @@ -739,8 +729,6 @@ void cfs_trace_flush_pages(void) struct cfs_trace_page *tage; struct cfs_trace_page *tmp; - spin_lock_init(&pc.pc_lock); - pc.pc_want_daemon_pages = 1; collect_pages(&pc); list_for_each_entry_safe(tage, tmp, &pc.pc_pages, linkage) { @@ -970,7 +958,6 @@ static int tracefiled(void *arg) /* we're started late enough that we pick up init's fs context */ /* this is so broken in uml? what on earth is going on? */ - spin_lock_init(&pc.pc_lock); complete(&tctl->tctl_start); while (1) { @@ -1170,7 +1157,6 @@ static void cfs_trace_cleanup(void) struct page_collection pc; INIT_LIST_HEAD(&pc.pc_pages); - spin_lock_init(&pc.pc_lock); trace_cleanup_on_all_cpus(); diff --git a/drivers/staging/lustre/lustre/libcfs/tracefile.h b/drivers/staging/lustre/lustre/libcfs/tracefile.h index cb7a396..de37fb7 100644 --- a/drivers/staging/lustre/lustre/libcfs/tracefile.h +++ b/drivers/staging/lustre/lustre/libcfs/tracefile.h @@ -196,14 +196,6 @@ extern union cfs_trace_data_union (*cfs_trace_data[TCD_MAX_TYPES])[NR_CPUS]; struct page_collection { struct list_head pc_pages; /* - * spin-lock protecting ->pc_pages. It is taken by smp_call_function() - * call-back functions. XXX nikita: Which is horrible: all processors - * receive NMI at the same time only to be serialized by this - * lock. Probably ->pc_pages should be replaced with an array of - * NR_CPUS elements accessed locklessly. - */ - spinlock_t pc_lock; - /* * if this flag is set, collect_pages() will spill both * ->tcd_daemon_pages and ->tcd_pages to the ->pc_pages. Otherwise, * only ->tcd_pages are spilled. -- 1.7.1 _______________________________________________ devel mailing list devel@xxxxxxxxxxxxxxxxxxxxxx http://driverdev.linuxdriverproject.org/mailman/listinfo/driverdev-devel
