[PATCH] backport sys_sendfile64

Christoph Hellwig (hch@lst.de)
Mon, 3 Mar 2003 20:09:20 +0100


To support sendfile() in LFS applications we need the sendfile64()
syscall that is different from sendfile() only in taking a loff_t offset
parameter instead of off_t. Obviously they share the actual
implementation so the patch is very small. sendfile64() is supported
in 2.5 and many vendor kernel for a long time and in -ac for a while
now.

--- 1.17/arch/i386/kernel/entry.S Sun Feb 9 21:30:42 2003
+++ edited/arch/i386/kernel/entry.S Mon Mar 3 19:04:16 2003
@@ -643,7 +643,7 @@
.long SYMBOL_NAME(sys_lremovexattr)
.long SYMBOL_NAME(sys_fremovexattr)
.long SYMBOL_NAME(sys_tkill)
- .long SYMBOL_NAME(sys_ni_syscall) /* reserved for sendfile64 */
+ .long SYMBOL_NAME(sys_sendfile64)
.long SYMBOL_NAME(sys_ni_syscall) /* 240 reserved for futex */
.long SYMBOL_NAME(sys_ni_syscall) /* reserved for sched_setaffinity */
.long SYMBOL_NAME(sys_ni_syscall) /* reserved for sched_getaffinity */
--- 1.75/mm/filemap.c Wed Feb 5 21:53:44 2003
+++ edited/mm/filemap.c Mon Mar 3 19:04:16 2003
@@ -1743,7 +1743,7 @@
return written;
}

-asmlinkage ssize_t sys_sendfile(int out_fd, int in_fd, off_t *offset, size_t count)
+static ssize_t common_sendfile(int out_fd, int in_fd, loff_t *offset, size_t count)
{
ssize_t retval;
struct file * in_file, * out_file;
@@ -1788,27 +1788,19 @@
retval = 0;
if (count) {
read_descriptor_t desc;
- loff_t pos = 0, *ppos;
-
- retval = -EFAULT;
- ppos = &in_file->f_pos;
- if (offset) {
- if (get_user(pos, offset))
- goto fput_out;
- ppos = &pos;
- }
+
+ if (!offset)
+ offset = &in_file->f_pos;

desc.written = 0;
desc.count = count;
desc.buf = (char *) out_file;
desc.error = 0;
- do_generic_file_read(in_file, ppos, &desc, file_send_actor);
+ do_generic_file_read(in_file, offset, &desc, file_send_actor);

retval = desc.written;
if (!retval)
retval = desc.error;
- if (offset)
- put_user(pos, offset);
}

fput_out:
@@ -1817,6 +1809,38 @@
fput(in_file);
out:
return retval;
+}
+
+asmlinkage ssize_t sys_sendfile(int out_fd, int in_fd, off_t *offset, size_t count)
+{
+ loff_t pos, *ppos = NULL;
+ ssize_t ret;
+ if (offset) {
+ off_t off;
+ if (unlikely(get_user(off, offset)))
+ return -EFAULT;
+ pos = off;
+ ppos = &pos;
+ }
+ ret = common_sendfile(out_fd, in_fd, ppos, count);
+ if (offset)
+ put_user((off_t)pos, offset);
+ return ret;
+}
+
+asmlinkage ssize_t sys_sendfile64(int out_fd, int in_fd, loff_t *offset, size_t count)
+{
+ loff_t pos, *ppos = NULL;
+ ssize_t ret;
+ if (offset) {
+ if (unlikely(copy_from_user(&pos, offset, sizeof(loff_t))))
+ return -EFAULT;
+ ppos = &pos;
+ }
+ ret = common_sendfile(out_fd, in_fd, ppos, count);
+ if (offset)
+ put_user(pos, offset);
+ return ret;
}

static ssize_t do_readahead(struct file *file, unsigned long index, unsigned long nr)
-
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