/* Copy the given number of bytes from one file to another.
* Uses provided src_ppos for src_file (or src_file->f_pos if NULL).
* "zerocopy" reads are used when the source has a readpage method.
*/
loff_t
cr_sendfile(cr_errbuf_t *eb, struct file *dst_filp, struct file *src_filp, loff_t *src_ppos, loff_t count)
{
#ifdef cr_generic_file_read
struct address_space *mapping;
#endif
if (!count) return 0;
if (!src_ppos) src_ppos = &src_filp->f_pos;
#ifdef HPAGE_SIZE
/* The generic methods don't work on hugetlbfs files */
if (is_file_hugepages(src_filp)) {
return cr_sendfile_hugesrc(eb, dst_filp, src_filp, src_ppos, count);
}
if (is_file_hugepages(dst_filp)) {
return cr_sendfile_hugedst(eb, dst_filp, src_filp, src_ppos, count);
}
#endif
#if HAVE_SPLICE_DIRECT_TO_ACTOR
/* Our 1st choice is splice_direct_to_actor(), when available and allowed. */
if (src_filp->f_op && src_filp->f_op->splice_read &&
dst_filp->f_op && dst_filp->f_op->splice_write) {
return cr_splice_direct(src_filp, src_ppos, dst_filp, count);
}
#endif
#ifdef cr_generic_file_read
/* Our 2nd choice algorithm is do_generic_file_read() + vfs_write()
* But this is not available w/ kernel >= 2.6.25 (hence the ifdef)
* nor is it available when the source is not mmap()able.
*/
mapping = src_filp->f_dentry->d_inode->i_mapping;
if (mapping && mapping->a_ops && mapping->a_ops->readpage) {
return cr_sendfile_generic_read(dst_filp, src_filp, src_ppos, count);
}
#endif
/* Final option is vfs_read() + vfs_write() */
return cr_sendfile_buffered(eb, dst_filp, src_filp, src_ppos, count);
}
/*
* shm_destroy - free the struct shmid_kernel
*
* @ns: namespace
* @shp: struct to free
*
* It has to be called with shp and shm_ids.rwsem (writer) locked,
* but returns with shp unlocked and freed.
*/
static void shm_destroy(struct ipc_namespace *ns, struct shmid_kernel *shp)
{
struct file *shm_file;
shm_file = shp->shm_file;
shp->shm_file = NULL;
ns->shm_tot -= (shp->shm_segsz + PAGE_SIZE - 1) >> PAGE_SHIFT;
shm_rmid(ns, shp);
shm_unlock(shp);
if (!is_file_hugepages(shm_file))
shmem_lock(shm_file, 0, shp->mlock_user);
else if (shp->mlock_user)
user_shm_unlock(file_inode(shm_file)->i_size, shp->mlock_user);
fput(shm_file);
ipc_rcu_putref(shp, shm_rcu_free);
}
