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iov_iter: Separate type from direction and use accessor functions

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In the iov_iter struct, separate the iterator type from the iterator
direction and use accessor functions to access them in most places.

Convert a bunch of places to use switch-statements to access them rather
then chains of bitwise-AND statements.  This makes it easier to add further
iterator types.  Also, this can be more efficient as to implement a switch
of small contiguous integers, the compiler can use ~50% fewer compare
instructions than it has to use bitwise-and instructions.

Further, cease passing the iterator type into the iterator setup function.
The iterator function can set that itself.  Only the direction is required.

Signed-off-by: David Howells <dhowells@redhat.com>
This commit is contained in:
David Howells
2018-10-20 00:57:56 +01:00
parent 00e2370744
commit aa563d7bca
40 changed files with 96 additions and 105 deletions
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6
drivers/target/target_core_file.c
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@@ -303,7 +303,7 @@ fd_execute_rw_aio(struct se_cmd *cmd, struct scatterlist *sgl, u32 sgl_nents,
len += sg->length;
}
iov_iter_bvec(&iter, ITER_BVEC | is_write, bvec, sgl_nents, len);
iov_iter_bvec(&iter, is_write, bvec, sgl_nents, len);
aio_cmd->cmd = cmd;
aio_cmd->len = len;
@@ -353,7 +353,7 @@ static int fd_do_rw(struct se_cmd *cmd, struct file *fd,
len += sg->length;
}
iov_iter_bvec(&iter, ITER_BVEC, bvec, sgl_nents, len);
iov_iter_bvec(&iter, READ, bvec, sgl_nents, len);
if (is_write)
ret = vfs_iter_write(fd, &iter, &pos, 0);
else
@@ -490,7 +490,7 @@ fd_execute_write_same(struct se_cmd *cmd)
len += se_dev->dev_attrib.block_size;
}
iov_iter_bvec(&iter, ITER_BVEC, bvec, nolb, len);
iov_iter_bvec(&iter, READ, bvec, nolb, len);
ret = vfs_iter_write(fd_dev->fd_file, &iter, &pos, 0);
kfree(bvec);