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author | Linus Torvalds <torvalds@linux-foundation.org> | 2014-08-16 08:56:27 -0600 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2014-08-16 08:56:27 -0600 |
commit | da06df548e2b82848bcc32342234d0f04340a41c (patch) | |
tree | 0f1d4a41cf6d1e6be924d1441ce1352ae2028fa4 /fs/aio.c | |
parent | 88ec63d6f85ccf40988ddae8b430dcb07355b29b (diff) | |
parent | 00fefb9cf2b5493a86912de55ba912bdfae4a207 (diff) | |
download | op-kernel-dev-da06df548e2b82848bcc32342234d0f04340a41c.zip op-kernel-dev-da06df548e2b82848bcc32342234d0f04340a41c.tar.gz |
Merge git://git.kvack.org/~bcrl/aio-next
Pull aio updates from Ben LaHaise.
* git://git.kvack.org/~bcrl/aio-next:
aio: use iovec array rather than the single one
aio: fix some comments
aio: use the macro rather than the inline magic number
aio: remove the needless registration of ring file's private_data
aio: remove no longer needed preempt_disable()
aio: kill the misleading rcu read locks in ioctx_add_table() and kill_ioctx()
aio: change exit_aio() to load mm->ioctx_table once and avoid rcu_read_lock()
Diffstat (limited to 'fs/aio.c')
-rw-r--r-- | fs/aio.c | 86 |
1 files changed, 30 insertions, 56 deletions
@@ -192,7 +192,6 @@ static struct file *aio_private_file(struct kioctx *ctx, loff_t nr_pages) } file->f_flags = O_RDWR; - file->private_data = ctx; return file; } @@ -202,7 +201,7 @@ static struct dentry *aio_mount(struct file_system_type *fs_type, static const struct dentry_operations ops = { .d_dname = simple_dname, }; - return mount_pseudo(fs_type, "aio:", NULL, &ops, 0xa10a10a1); + return mount_pseudo(fs_type, "aio:", NULL, &ops, AIO_RING_MAGIC); } /* aio_setup @@ -556,8 +555,7 @@ static int ioctx_add_table(struct kioctx *ctx, struct mm_struct *mm) struct aio_ring *ring; spin_lock(&mm->ioctx_lock); - rcu_read_lock(); - table = rcu_dereference(mm->ioctx_table); + table = rcu_dereference_raw(mm->ioctx_table); while (1) { if (table) @@ -565,7 +563,6 @@ static int ioctx_add_table(struct kioctx *ctx, struct mm_struct *mm) if (!table->table[i]) { ctx->id = i; table->table[i] = ctx; - rcu_read_unlock(); spin_unlock(&mm->ioctx_lock); /* While kioctx setup is in progress, @@ -579,8 +576,6 @@ static int ioctx_add_table(struct kioctx *ctx, struct mm_struct *mm) } new_nr = (table ? table->nr : 1) * 4; - - rcu_read_unlock(); spin_unlock(&mm->ioctx_lock); table = kzalloc(sizeof(*table) + sizeof(struct kioctx *) * @@ -591,8 +586,7 @@ static int ioctx_add_table(struct kioctx *ctx, struct mm_struct *mm) table->nr = new_nr; spin_lock(&mm->ioctx_lock); - rcu_read_lock(); - old = rcu_dereference(mm->ioctx_table); + old = rcu_dereference_raw(mm->ioctx_table); if (!old) { rcu_assign_pointer(mm->ioctx_table, table); @@ -739,12 +733,9 @@ static int kill_ioctx(struct mm_struct *mm, struct kioctx *ctx, spin_lock(&mm->ioctx_lock); - rcu_read_lock(); - table = rcu_dereference(mm->ioctx_table); - + table = rcu_dereference_raw(mm->ioctx_table); WARN_ON(ctx != table->table[ctx->id]); table->table[ctx->id] = NULL; - rcu_read_unlock(); spin_unlock(&mm->ioctx_lock); /* percpu_ref_kill() will do the necessary call_rcu() */ @@ -793,40 +784,30 @@ EXPORT_SYMBOL(wait_on_sync_kiocb); */ void exit_aio(struct mm_struct *mm) { - struct kioctx_table *table; - struct kioctx *ctx; - unsigned i = 0; - - while (1) { - rcu_read_lock(); - table = rcu_dereference(mm->ioctx_table); - - do { - if (!table || i >= table->nr) { - rcu_read_unlock(); - rcu_assign_pointer(mm->ioctx_table, NULL); - if (table) - kfree(table); - return; - } + struct kioctx_table *table = rcu_dereference_raw(mm->ioctx_table); + int i; - ctx = table->table[i++]; - } while (!ctx); + if (!table) + return; - rcu_read_unlock(); + for (i = 0; i < table->nr; ++i) { + struct kioctx *ctx = table->table[i]; + if (!ctx) + continue; /* - * We don't need to bother with munmap() here - - * exit_mmap(mm) is coming and it'll unmap everything. - * Since aio_free_ring() uses non-zero ->mmap_size - * as indicator that it needs to unmap the area, - * just set it to 0; aio_free_ring() is the only - * place that uses ->mmap_size, so it's safe. + * We don't need to bother with munmap() here - exit_mmap(mm) + * is coming and it'll unmap everything. And we simply can't, + * this is not necessarily our ->mm. + * Since kill_ioctx() uses non-zero ->mmap_size as indicator + * that it needs to unmap the area, just set it to 0. */ ctx->mmap_size = 0; - kill_ioctx(mm, ctx, NULL); } + + RCU_INIT_POINTER(mm->ioctx_table, NULL); + kfree(table); } static void put_reqs_available(struct kioctx *ctx, unsigned nr) @@ -834,10 +815,8 @@ static void put_reqs_available(struct kioctx *ctx, unsigned nr) struct kioctx_cpu *kcpu; unsigned long flags; - preempt_disable(); - kcpu = this_cpu_ptr(ctx->cpu); - local_irq_save(flags); + kcpu = this_cpu_ptr(ctx->cpu); kcpu->reqs_available += nr; while (kcpu->reqs_available >= ctx->req_batch * 2) { @@ -846,7 +825,6 @@ static void put_reqs_available(struct kioctx *ctx, unsigned nr) } local_irq_restore(flags); - preempt_enable(); } static bool get_reqs_available(struct kioctx *ctx) @@ -855,10 +833,8 @@ static bool get_reqs_available(struct kioctx *ctx) bool ret = false; unsigned long flags; - preempt_disable(); - kcpu = this_cpu_ptr(ctx->cpu); - local_irq_save(flags); + kcpu = this_cpu_ptr(ctx->cpu); if (!kcpu->reqs_available) { int old, avail = atomic_read(&ctx->reqs_available); @@ -878,7 +854,6 @@ static bool get_reqs_available(struct kioctx *ctx) kcpu->reqs_available--; out: local_irq_restore(flags); - preempt_enable(); return ret; } @@ -1047,7 +1022,7 @@ void aio_complete(struct kiocb *iocb, long res, long res2) } EXPORT_SYMBOL(aio_complete); -/* aio_read_events +/* aio_read_events_ring * Pull an event off of the ioctx's event ring. Returns the number of * events fetched */ @@ -1270,12 +1245,12 @@ static ssize_t aio_setup_vectored_rw(struct kiocb *kiocb, if (compat) ret = compat_rw_copy_check_uvector(rw, (struct compat_iovec __user *)buf, - *nr_segs, 1, *iovec, iovec); + *nr_segs, UIO_FASTIOV, *iovec, iovec); else #endif ret = rw_copy_check_uvector(rw, (struct iovec __user *)buf, - *nr_segs, 1, *iovec, iovec); + *nr_segs, UIO_FASTIOV, *iovec, iovec); if (ret < 0) return ret; @@ -1299,9 +1274,8 @@ static ssize_t aio_setup_single_vector(struct kiocb *kiocb, } /* - * aio_setup_iocb: - * Performs the initial checks and aio retry method - * setup for the kiocb at the time of io submission. + * aio_run_iocb: + * Performs the initial checks and io submission. */ static ssize_t aio_run_iocb(struct kiocb *req, unsigned opcode, char __user *buf, bool compat) @@ -1313,7 +1287,7 @@ static ssize_t aio_run_iocb(struct kiocb *req, unsigned opcode, fmode_t mode; aio_rw_op *rw_op; rw_iter_op *iter_op; - struct iovec inline_vec, *iovec = &inline_vec; + struct iovec inline_vecs[UIO_FASTIOV], *iovec = inline_vecs; struct iov_iter iter; switch (opcode) { @@ -1348,7 +1322,7 @@ rw_common: if (!ret) ret = rw_verify_area(rw, file, &req->ki_pos, req->ki_nbytes); if (ret < 0) { - if (iovec != &inline_vec) + if (iovec != inline_vecs) kfree(iovec); return ret; } @@ -1395,7 +1369,7 @@ rw_common: return -EINVAL; } - if (iovec != &inline_vec) + if (iovec != inline_vecs) kfree(iovec); if (ret != -EIOCBQUEUED) { |