From 93b071139a956e51c98cdefd50a47981a4eb852e Mon Sep 17 00:00:00 2001 From: Akinobu Mita Date: Thu, 5 Jun 2008 22:46:21 -0700 Subject: introduce memory_read_from_buffer() This patch introduces memory_read_from_buffer(). The only difference between memory_read_from_buffer() and simple_read_from_buffer() is which address space the function copies to. simple_read_from_buffer copies to user space memory. memory_read_from_buffer copies to normal memory. Signed-off-by: Akinobu Mita Cc: Al Viro Cc: Doug Warzecha Cc: Zhang Rui Cc: Matt Domsch Cc: Abhay Salunke Cc: Greg Kroah-Hartman Cc: Markus Rechberger Cc: Kay Sievers Cc: Bob Moore Cc: Thomas Renninger Cc: Len Brown Cc: Benjamin Herrenschmidt Cc: "Antonino A. Daplas" Cc: Krzysztof Helt Cc: Geert Uytterhoeven Cc: Martin Schwidefsky Cc: Heiko Carstens Cc: Peter Oberparleiter Cc: Michael Holzheu Cc: Brian King Cc: James E.J. Bottomley Cc: Andrew Vasquez Cc: Seokmann Ju Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- fs/libfs.c | 18 ++++++++++++++++++ 1 file changed, 18 insertions(+) (limited to 'fs/libfs.c') diff --git a/fs/libfs.c b/fs/libfs.c index b004dfadd89..892d41cb338 100644 --- a/fs/libfs.c +++ b/fs/libfs.c @@ -528,6 +528,23 @@ ssize_t simple_read_from_buffer(void __user *to, size_t count, loff_t *ppos, return count; } +ssize_t memory_read_from_buffer(void *to, size_t count, loff_t *ppos, + const void *from, size_t available) +{ + loff_t pos = *ppos; + + if (pos < 0) + return -EINVAL; + if (pos >= available) + return 0; + if (count > available - pos) + count = available - pos; + memcpy(to, from + pos, count); + *ppos = pos + count; + + return count; +} + /* * Transaction based IO. * The file expects a single write which triggers the transaction, and then @@ -800,6 +817,7 @@ EXPORT_SYMBOL(simple_statfs); EXPORT_SYMBOL(simple_sync_file); EXPORT_SYMBOL(simple_unlink); EXPORT_SYMBOL(simple_read_from_buffer); +EXPORT_SYMBOL(memory_read_from_buffer); EXPORT_SYMBOL(simple_transaction_get); EXPORT_SYMBOL(simple_transaction_read); EXPORT_SYMBOL(simple_transaction_release); -- cgit v1.2.3-70-g09d2 From 6d1029b56329b1cc9b7233e5333c1a48ddbbfad8 Mon Sep 17 00:00:00 2001 From: Akinobu Mita Date: Fri, 4 Jul 2008 09:59:51 -0700 Subject: add kernel-doc for simple_read_from_buffer and memory_read_from_buffer Add kernel-doc comments describing simple_read_from_buffer and memory_read_from_buffer. Signed-off-by: Akinobu Mita Cc: Christoph Hellwig Cc: "Randy.Dunlap" Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- fs/libfs.c | 28 ++++++++++++++++++++++++++++ 1 file changed, 28 insertions(+) (limited to 'fs/libfs.c') diff --git a/fs/libfs.c b/fs/libfs.c index 892d41cb338..baeb71ee1cd 100644 --- a/fs/libfs.c +++ b/fs/libfs.c @@ -512,6 +512,20 @@ void simple_release_fs(struct vfsmount **mount, int *count) mntput(mnt); } +/** + * simple_read_from_buffer - copy data from the buffer to user space + * @to: the user space buffer to read to + * @count: the maximum number of bytes to read + * @ppos: the current position in the buffer + * @from: the buffer to read from + * @available: the size of the buffer + * + * The simple_read_from_buffer() function reads up to @count bytes from the + * buffer @from at offset @ppos into the user space address starting at @to. + * + * On success, the number of bytes read is returned and the offset @ppos is + * advanced by this number, or negative value is returned on error. + **/ ssize_t simple_read_from_buffer(void __user *to, size_t count, loff_t *ppos, const void *from, size_t available) { @@ -528,6 +542,20 @@ ssize_t simple_read_from_buffer(void __user *to, size_t count, loff_t *ppos, return count; } +/** + * memory_read_from_buffer - copy data from the buffer + * @to: the kernel space buffer to read to + * @count: the maximum number of bytes to read + * @ppos: the current position in the buffer + * @from: the buffer to read from + * @available: the size of the buffer + * + * The memory_read_from_buffer() function reads up to @count bytes from the + * buffer @from at offset @ppos into the kernel space address starting at @to. + * + * On success, the number of bytes read is returned and the offset @ppos is + * advanced by this number, or negative value is returned on error. + **/ ssize_t memory_read_from_buffer(void *to, size_t count, loff_t *ppos, const void *from, size_t available) { -- cgit v1.2.3-70-g09d2