sys_swapon: remove did_down variable (83ef99be) · Commits · 戴 / test

Since mutex_lock(&inode->i_mutex) is called just after setting inode, did_down is always equivalent to (inode && S_ISREG(inode->i_mode)). Use this fact to remove the did_down variable. Signed-off-by:

Cesar Eduardo Barros <cesarb@cesarb.net> Tested-by:

Eric B Munson <emunson@mgebm.net> Acked-by:

Eric B Munson <emunson@mgebm.net> Reviewed-by:

KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Hugh Dickins <hughd@google.com> Signed-off-by:

Andrew Morton <akpm@linux-foundation.org> Signed-off-by:

Linus Torvalds <torvalds@linux-foundation.org>

mm/swapfile.c

+2 −6

Original line number	Diff line number	Diff line
		@@ -1907,7 +1907,6 @@ SYSCALL_DEFINE2(swapon, const char __user *, specialfile, int, swap_flags)
		unsigned char *swap_map = NULL;
		struct page *page = NULL;
		struct inode *inode = NULL;
		int did_down = 0;

		if (!capable(CAP_SYS_ADMIN))
		return -EPERM;
		@@ -1962,7 +1961,6 @@ SYSCALL_DEFINE2(swapon, const char __user *, specialfile, int, swap_flags)
		} else if (S_ISREG(inode->i_mode)) {
		p->bdev = inode->i_sb->s_bdev;
		mutex_lock(&inode->i_mutex);
		did_down = 1;
		if (IS_SWAPFILE(inode)) {
		error = -EBUSY;
		goto bad_swap;
		@@ -2154,10 +2152,8 @@ bad_swap_2:
		spin_unlock(&swap_lock);
		vfree(swap_map);
		if (swap_file) {
		if (did_down) {
		if (inode && S_ISREG(inode->i_mode))
		mutex_unlock(&inode->i_mutex);
		did_down = 0;
		}
		filp_close(swap_file, NULL);
		}
		out:
		@@ -2167,7 +2163,7 @@ out:
		}
		if (name)
		putname(name);
		if (did_down) {
		if (inode && S_ISREG(inode->i_mode)) {
		if (!error)
		inode->i_flags \|= S_SWAPFILE;
		mutex_unlock(&inode->i_mutex);

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