linux-2.6.33/__blockdev_direct_IO
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開始行:
*参照元 [#x40dcf69]
#backlinks
*説明 [#n2fb029f]
-パス: [[linux-2.6.33/fs/direct-io.c]]
-FIXME: これは何？
--説明
**引数 [#qb274b75]
-int rw
--
-struct kiocb *iocb
--
--[[linux-2.6.33/kiocb]]
-struct inode *inode
--
--[[linux-2.6.33/inode]]
-struct block_device *bdev
--
--[[linux-2.6.33/block_device]]
-const struct iovec *iov
--
--[[linux-2.6.33/iovec]]
-loff_t offset
--
-unsigned long nr_segs
--
-get_block_t get_block
--
--[[linux-2.6.33/get_block_t]]
-dio_iodone_t end_io
--
--[[linux-2.6.33/dio_iodone_t]]
--int flags
--
**返り値 [#hfff5a72]
-ssize_t
--
**参考 [#b6fe5875]
*実装 [#n34ab5cd]
/*
* This is a library function for use by filesystem driv...
*
* The locking rules are governed by the flags parameter:
* - if the flags value contains DIO_LOCKING we use a f...
* scheme for dumb filesystems.
* For writes this function is called under i_mutex a...
* i_mutex held, for reads, i_mutex is not held on en...
* taken and dropped again before returning.
* For reads and writes i_alloc_sem is taken in share...
* on I/O completion (which may happen asynchronously...
* the caller).
*
* - if the flags value does NOT contain DIO_LOCKING we...
* internal locking but rather rely on the filesystem...
* direct I/O reads/writes versus each other and trun...
* For reads and writes both i_mutex and i_alloc_sem ...
* entry and are never taken.
*/
ssize_t
__blockdev_direct_IO(int rw, struct kiocb *iocb, struct ...
struct block_device *bdev, const struct iovec *iov, lof...
unsigned long nr_segs, get_block_t get_block, dio_iodon...
int flags)
{
int seg;
size_t size;
unsigned long addr;
unsigned blkbits = inode->i_blkbits;
unsigned bdev_blkbits = 0;
unsigned blocksize_mask = (1 << blkbits) - 1;
ssize_t retval = -EINVAL;
loff_t end = offset;
struct dio *dio;
-
--[[linux-2.6.33/dio]]
if (rw & WRITE)
rw = WRITE_ODIRECT_PLUG;
-
--[[linux-2.6.33/WRITE]]
--[[linux-2.6.33/WRITE_ODIRECT_PLUG]]
if (bdev)
bdev_blkbits = blksize_bits(bdev_logical_block_size(bd...
-
--[[linux-2.6.33/blksize_bits()]]
--[[linux-2.6.33/bdev_logical_block_size()]]
if (offset & blocksize_mask) {
if (bdev)
blkbits = bdev_blkbits;
blocksize_mask = (1 << blkbits) - 1;
if (offset & blocksize_mask)
goto out;
}
/* Check the memory alignment. Blocks cannot straddle ...
for (seg = 0; seg < nr_segs; seg++) {
addr = (unsigned long)iov[seg].iov_base;
size = iov[seg].iov_len;
end += size;
if ((addr & blocksize_mask) || (size & blocksize_mask)...
if (bdev)
blkbits = bdev_blkbits;
blocksize_mask = (1 << blkbits) - 1;
if ((addr & blocksize_mask) || (size & blocksize_mask...
goto out;
}
}
dio = kmalloc(sizeof(*dio), GFP_KERNEL);
retval = -ENOMEM;
if (!dio)
goto out;
-
--[[linux-2.6.33/kmalloc()]]
/*
* Believe it or not, zeroing out the page array caused...
* performance regression in a database benchmark. So,...
* care to only zero out what's needed.
*/
memset(dio, 0, offsetof(struct dio, pages));
-
--[[linux-2.6.33/memset()]]
dio->flags = flags;
if (dio->flags & DIO_LOCKING) {
-
--[[linux-2.6.33/DIO_LOCKING]]
/* watch out for a 0 len io from a tricksy fs */
if (rw == READ && end > offset) {
struct address_space *mapping =
iocb->ki_filp->f_mapping;
/* will be released by direct_io_worker */
mutex_lock(&inode->i_mutex);
-
--[[linux-2.6.33/mutex_lock()]]
retval = filemap_write_and_wait_range(mapping, offset,
end - 1);
if (retval) {
mutex_unlock(&inode->i_mutex);
kfree(dio);
goto out;
}
-
--[[linux-2.6.33/filemap_write_and_wait_range()]]
--[[linux-2.6.33/mutex_unlock()]]
--[[linux-2.6.33/kfree()]]
}
/*
* Will be released at I/O completion, possibly in a
* different thread.
*/
down_read_non_owner(&inode->i_alloc_sem);
-
--[[linux-2.6.33/down_read_non_owner()]]
}
/*
* For file extending writes updating i_size before data
* writeouts complete can expose uninitialized blocks. So
* even for AIO, we need to wait for i/o to complete be...
* returning in this case.
*/
dio->is_async = !is_sync_kiocb(iocb) && !((rw & WRITE) &&
(end > i_size_read(inode)));
-
--[[linux-2.6.33/is_sync_kiocb()]]
--[[linux-2.6.33/i_size_read()]]
retval = direct_io_worker(rw, iocb, inode, iov, offset,
nr_segs, blkbits, get_block, end_io, dio);
-
--[[linux-2.6.33/direct_io_worker()]]
/*
* In case of error extending write may have instantiat...
* blocks outside i_size. Trim these off again for DIO_...
*
* NOTE: filesystems with their own locking have to han...
* on their own.
*/
if (flags & DIO_LOCKING) {
if (unlikely((rw & WRITE) && retval < 0)) {
loff_t isize = i_size_read(inode);
if (end > isize)
vmtruncate(inode, isize);
}
-
--[[linux-2.6.33/vmtruncate()]]
}
out:
return retval;
}
EXPORT_SYMBOL(__blockdev_direct_IO);
-特にライセンスを区別せず関数をエクスポートする。
--[[linux-2.6.33/EXPORT_SYMBOL()]]
*コメント [#t0f61807]
終了行:
*参照元 [#x40dcf69]
#backlinks
*説明 [#n2fb029f]
-パス: [[linux-2.6.33/fs/direct-io.c]]
-FIXME: これは何？
--説明
**引数 [#qb274b75]
-int rw
--
-struct kiocb *iocb
--
--[[linux-2.6.33/kiocb]]
-struct inode *inode
--
--[[linux-2.6.33/inode]]
-struct block_device *bdev
--
--[[linux-2.6.33/block_device]]
-const struct iovec *iov
--
--[[linux-2.6.33/iovec]]
-loff_t offset
--
-unsigned long nr_segs
--
-get_block_t get_block
--
--[[linux-2.6.33/get_block_t]]
-dio_iodone_t end_io
--
--[[linux-2.6.33/dio_iodone_t]]
--int flags
--
**返り値 [#hfff5a72]
-ssize_t
--
**参考 [#b6fe5875]
*実装 [#n34ab5cd]
/*
* This is a library function for use by filesystem driv...
*
* The locking rules are governed by the flags parameter:
* - if the flags value contains DIO_LOCKING we use a f...
* scheme for dumb filesystems.
* For writes this function is called under i_mutex a...
* i_mutex held, for reads, i_mutex is not held on en...
* taken and dropped again before returning.
* For reads and writes i_alloc_sem is taken in share...
* on I/O completion (which may happen asynchronously...
* the caller).
*
* - if the flags value does NOT contain DIO_LOCKING we...
* internal locking but rather rely on the filesystem...
* direct I/O reads/writes versus each other and trun...
* For reads and writes both i_mutex and i_alloc_sem ...
* entry and are never taken.
*/
ssize_t
__blockdev_direct_IO(int rw, struct kiocb *iocb, struct ...
struct block_device *bdev, const struct iovec *iov, lof...
unsigned long nr_segs, get_block_t get_block, dio_iodon...
int flags)
{
int seg;
size_t size;
unsigned long addr;
unsigned blkbits = inode->i_blkbits;
unsigned bdev_blkbits = 0;
unsigned blocksize_mask = (1 << blkbits) - 1;
ssize_t retval = -EINVAL;
loff_t end = offset;
struct dio *dio;
-
--[[linux-2.6.33/dio]]
if (rw & WRITE)
rw = WRITE_ODIRECT_PLUG;
-
--[[linux-2.6.33/WRITE]]
--[[linux-2.6.33/WRITE_ODIRECT_PLUG]]
if (bdev)
bdev_blkbits = blksize_bits(bdev_logical_block_size(bd...
-
--[[linux-2.6.33/blksize_bits()]]
--[[linux-2.6.33/bdev_logical_block_size()]]
if (offset & blocksize_mask) {
if (bdev)
blkbits = bdev_blkbits;
blocksize_mask = (1 << blkbits) - 1;
if (offset & blocksize_mask)
goto out;
}
/* Check the memory alignment. Blocks cannot straddle ...
for (seg = 0; seg < nr_segs; seg++) {
addr = (unsigned long)iov[seg].iov_base;
size = iov[seg].iov_len;
end += size;
if ((addr & blocksize_mask) || (size & blocksize_mask)...
if (bdev)
blkbits = bdev_blkbits;
blocksize_mask = (1 << blkbits) - 1;
if ((addr & blocksize_mask) || (size & blocksize_mask...
goto out;
}
}
dio = kmalloc(sizeof(*dio), GFP_KERNEL);
retval = -ENOMEM;
if (!dio)
goto out;
-
--[[linux-2.6.33/kmalloc()]]
/*
* Believe it or not, zeroing out the page array caused...
* performance regression in a database benchmark. So,...
* care to only zero out what's needed.
*/
memset(dio, 0, offsetof(struct dio, pages));
-
--[[linux-2.6.33/memset()]]
dio->flags = flags;
if (dio->flags & DIO_LOCKING) {
-
--[[linux-2.6.33/DIO_LOCKING]]
/* watch out for a 0 len io from a tricksy fs */
if (rw == READ && end > offset) {
struct address_space *mapping =
iocb->ki_filp->f_mapping;
/* will be released by direct_io_worker */
mutex_lock(&inode->i_mutex);
-
--[[linux-2.6.33/mutex_lock()]]
retval = filemap_write_and_wait_range(mapping, offset,
end - 1);
if (retval) {
mutex_unlock(&inode->i_mutex);
kfree(dio);
goto out;
}
-
--[[linux-2.6.33/filemap_write_and_wait_range()]]
--[[linux-2.6.33/mutex_unlock()]]
--[[linux-2.6.33/kfree()]]
}
/*
* Will be released at I/O completion, possibly in a
* different thread.
*/
down_read_non_owner(&inode->i_alloc_sem);
-
--[[linux-2.6.33/down_read_non_owner()]]
}
/*
* For file extending writes updating i_size before data
* writeouts complete can expose uninitialized blocks. So
* even for AIO, we need to wait for i/o to complete be...
* returning in this case.
*/
dio->is_async = !is_sync_kiocb(iocb) && !((rw & WRITE) &&
(end > i_size_read(inode)));
-
--[[linux-2.6.33/is_sync_kiocb()]]
--[[linux-2.6.33/i_size_read()]]
retval = direct_io_worker(rw, iocb, inode, iov, offset,
nr_segs, blkbits, get_block, end_io, dio);
-
--[[linux-2.6.33/direct_io_worker()]]
/*
* In case of error extending write may have instantiat...
* blocks outside i_size. Trim these off again for DIO_...
*
* NOTE: filesystems with their own locking have to han...
* on their own.
*/
if (flags & DIO_LOCKING) {
if (unlikely((rw & WRITE) && retval < 0)) {
loff_t isize = i_size_read(inode);
if (end > isize)
vmtruncate(inode, isize);
}
-
--[[linux-2.6.33/vmtruncate()]]
}
out:
return retval;
}
EXPORT_SYMBOL(__blockdev_direct_IO);
-特にライセンスを区別せず関数をエクスポートする。
--[[linux-2.6.33/EXPORT_SYMBOL()]]
*コメント [#t0f61807]
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