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authorLinus Torvalds <torvalds@linux-foundation.org>2018-01-31 09:25:20 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2018-01-31 09:25:20 -0800
commit19e7b5f99474107e8d0b4b3e4652fa19ddb87efc (patch)
tree49f15b76c07b4c90d6fbd17b49d69017c81a4b58 /fs/eventfd.c
parent26064ea409b4d4acb05903a36f3fe2fdccb3d8aa (diff)
parentce4c253573ad184603e0fa77876ba155b0cde46d (diff)
Merge branch 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
Pull misc vfs updates from Al Viro: "All kinds of misc stuff, without any unifying topic, from various people. Neil's d_anon patch, several bugfixes, introduction of kvmalloc analogue of kmemdup_user(), extending bitfield.h to deal with fixed-endians, assorted cleanups all over the place..." * 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (28 commits) alpha: osf_sys.c: use timespec64 where appropriate alpha: osf_sys.c: fix put_tv32 regression jffs2: Fix use-after-free bug in jffs2_iget()'s error handling path dcache: delete unused d_hash_mask dcache: subtract d_hash_shift from 32 in advance fs/buffer.c: fold init_buffer() into init_page_buffers() fs: fold __inode_permission() into inode_permission() fs: add RWF_APPEND sctp: use vmemdup_user() rather than badly open-coding memdup_user() snd_ctl_elem_init_enum_names(): switch to vmemdup_user() replace_user_tlv(): switch to vmemdup_user() new primitive: vmemdup_user() memdup_user(): switch to GFP_USER eventfd: fold eventfd_ctx_get() into eventfd_ctx_fileget() eventfd: fold eventfd_ctx_read() into eventfd_read() eventfd: convert to use anon_inode_getfd() nfs4file: get rid of pointless include of btrfs.h uvc_v4l2: clean copyin/copyout up vme_user: don't use __copy_..._user() usx2y: don't bother with memdup_user() for 16-byte structure ...
Diffstat (limited to 'fs/eventfd.c')
-rw-r--r--fs/eventfd.c127
1 files changed, 28 insertions, 99 deletions
diff --git a/fs/eventfd.c b/fs/eventfd.c
index 6318a9b57e53..04fd824142a1 100644
--- a/fs/eventfd.c
+++ b/fs/eventfd.c
@@ -80,24 +80,11 @@ static void eventfd_free(struct kref *kref)
}
/**
- * eventfd_ctx_get - Acquires a reference to the internal eventfd context.
- * @ctx: [in] Pointer to the eventfd context.
- *
- * Returns: In case of success, returns a pointer to the eventfd context.
- */
-struct eventfd_ctx *eventfd_ctx_get(struct eventfd_ctx *ctx)
-{
- kref_get(&ctx->kref);
- return ctx;
-}
-EXPORT_SYMBOL_GPL(eventfd_ctx_get);
-
-/**
* eventfd_ctx_put - Releases a reference to the internal eventfd context.
* @ctx: [in] Pointer to eventfd context.
*
* The eventfd context reference must have been previously acquired either
- * with eventfd_ctx_get() or eventfd_ctx_fdget().
+ * with eventfd_ctx_fdget() or eventfd_ctx_fileget().
*/
void eventfd_ctx_put(struct eventfd_ctx *ctx)
{
@@ -207,36 +194,27 @@ int eventfd_ctx_remove_wait_queue(struct eventfd_ctx *ctx, wait_queue_entry_t *w
}
EXPORT_SYMBOL_GPL(eventfd_ctx_remove_wait_queue);
-/**
- * eventfd_ctx_read - Reads the eventfd counter or wait if it is zero.
- * @ctx: [in] Pointer to eventfd context.
- * @no_wait: [in] Different from zero if the operation should not block.
- * @cnt: [out] Pointer to the 64-bit counter value.
- *
- * Returns %0 if successful, or the following error codes:
- *
- * - -EAGAIN : The operation would have blocked but @no_wait was non-zero.
- * - -ERESTARTSYS : A signal interrupted the wait operation.
- *
- * If @no_wait is zero, the function might sleep until the eventfd internal
- * counter becomes greater than zero.
- */
-ssize_t eventfd_ctx_read(struct eventfd_ctx *ctx, int no_wait, __u64 *cnt)
+static ssize_t eventfd_read(struct file *file, char __user *buf, size_t count,
+ loff_t *ppos)
{
+ struct eventfd_ctx *ctx = file->private_data;
ssize_t res;
+ __u64 ucnt = 0;
DECLARE_WAITQUEUE(wait, current);
+ if (count < sizeof(ucnt))
+ return -EINVAL;
+
spin_lock_irq(&ctx->wqh.lock);
- *cnt = 0;
res = -EAGAIN;
if (ctx->count > 0)
- res = 0;
- else if (!no_wait) {
+ res = sizeof(ucnt);
+ else if (!(file->f_flags & O_NONBLOCK)) {
__add_wait_queue(&ctx->wqh, &wait);
for (;;) {
set_current_state(TASK_INTERRUPTIBLE);
if (ctx->count > 0) {
- res = 0;
+ res = sizeof(ucnt);
break;
}
if (signal_pending(current)) {
@@ -250,31 +228,17 @@ ssize_t eventfd_ctx_read(struct eventfd_ctx *ctx, int no_wait, __u64 *cnt)
__remove_wait_queue(&ctx->wqh, &wait);
__set_current_state(TASK_RUNNING);
}
- if (likely(res == 0)) {
- eventfd_ctx_do_read(ctx, cnt);
+ if (likely(res > 0)) {
+ eventfd_ctx_do_read(ctx, &ucnt);
if (waitqueue_active(&ctx->wqh))
wake_up_locked_poll(&ctx->wqh, POLLOUT);
}
spin_unlock_irq(&ctx->wqh.lock);
- return res;
-}
-EXPORT_SYMBOL_GPL(eventfd_ctx_read);
-
-static ssize_t eventfd_read(struct file *file, char __user *buf, size_t count,
- loff_t *ppos)
-{
- struct eventfd_ctx *ctx = file->private_data;
- ssize_t res;
- __u64 cnt;
-
- if (count < sizeof(cnt))
- return -EINVAL;
- res = eventfd_ctx_read(ctx, file->f_flags & O_NONBLOCK, &cnt);
- if (res < 0)
- return res;
+ if (res > 0 && put_user(ucnt, (__u64 __user *)buf))
+ return -EFAULT;
- return put_user(cnt, (__u64 __user *) buf) ? -EFAULT : sizeof(cnt);
+ return res;
}
static ssize_t eventfd_write(struct file *file, const char __user *buf, size_t count,
@@ -405,79 +369,44 @@ EXPORT_SYMBOL_GPL(eventfd_ctx_fdget);
*/
struct eventfd_ctx *eventfd_ctx_fileget(struct file *file)
{
+ struct eventfd_ctx *ctx;
+
if (file->f_op != &eventfd_fops)
return ERR_PTR(-EINVAL);
- return eventfd_ctx_get(file->private_data);
+ ctx = file->private_data;
+ kref_get(&ctx->kref);
+ return ctx;
}
EXPORT_SYMBOL_GPL(eventfd_ctx_fileget);
-/**
- * eventfd_file_create - Creates an eventfd file pointer.
- * @count: Initial eventfd counter value.
- * @flags: Flags for the eventfd file.
- *
- * This function creates an eventfd file pointer, w/out installing it into
- * the fd table. This is useful when the eventfd file is used during the
- * initialization of data structures that require extra setup after the eventfd
- * creation. So the eventfd creation is split into the file pointer creation
- * phase, and the file descriptor installation phase.
- * In this way races with userspace closing the newly installed file descriptor
- * can be avoided.
- * Returns an eventfd file pointer, or a proper error pointer.
- */
-struct file *eventfd_file_create(unsigned int count, int flags)
+SYSCALL_DEFINE2(eventfd2, unsigned int, count, int, flags)
{
- struct file *file;
struct eventfd_ctx *ctx;
+ int fd;
/* Check the EFD_* constants for consistency. */
BUILD_BUG_ON(EFD_CLOEXEC != O_CLOEXEC);
BUILD_BUG_ON(EFD_NONBLOCK != O_NONBLOCK);
if (flags & ~EFD_FLAGS_SET)
- return ERR_PTR(-EINVAL);
+ return -EINVAL;
ctx = kmalloc(sizeof(*ctx), GFP_KERNEL);
if (!ctx)
- return ERR_PTR(-ENOMEM);
+ return -ENOMEM;
kref_init(&ctx->kref);
init_waitqueue_head(&ctx->wqh);
ctx->count = count;
ctx->flags = flags;
- file = anon_inode_getfile("[eventfd]", &eventfd_fops, ctx,
- O_RDWR | (flags & EFD_SHARED_FCNTL_FLAGS));
- if (IS_ERR(file))
+ fd = anon_inode_getfd("[eventfd]", &eventfd_fops, ctx,
+ O_RDWR | (flags & EFD_SHARED_FCNTL_FLAGS));
+ if (fd < 0)
eventfd_free_ctx(ctx);
- return file;
-}
-
-SYSCALL_DEFINE2(eventfd2, unsigned int, count, int, flags)
-{
- int fd, error;
- struct file *file;
-
- error = get_unused_fd_flags(flags & EFD_SHARED_FCNTL_FLAGS);
- if (error < 0)
- return error;
- fd = error;
-
- file = eventfd_file_create(count, flags);
- if (IS_ERR(file)) {
- error = PTR_ERR(file);
- goto err_put_unused_fd;
- }
- fd_install(fd, file);
-
return fd;
-
-err_put_unused_fd:
- put_unused_fd(fd);
-
- return error;
}
SYSCALL_DEFINE1(eventfd, unsigned int, count)