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From: Eric Van Hensbergen <ericvh@kernel.org>
Date: Mon, 08 Jan 2024 15:18:22 +0000
Subject: [PATCH v2 6/8] fs/9p: rework qid2ino logic
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Message-Id: <20240108-ericvh-fix-cache-dups-v2-6-a73f8822838c@kernel.org>
References: <20240108-ericvh-fix-cache-dups-v2-0-a73f8822838c@kernel.org>
In-Reply-To: <20240108-ericvh-fix-cache-dups-v2-0-a73f8822838c@kernel.org>
To: Latchesar Ionkov <lucho@ionkov.net>, 
 Dominique Martinet <asmadeus@codewreck.org>, 
 Christian Schoenebeck <linux_oss@crudebyte.com>
Cc: v9fs@lists.linux.dev, linux-kernel@vger.kernel.org, 
 Eric Van Hensbergen <ericvh@kernel.org>

This changes from a function to a macro because we can
figure out if we are 32 or 64 bit at compile time.

Signed-off-by: Eric Van Hensbergen <ericvh@kernel.org>
---
 fs/9p/v9fs_vfs.h       |  7 ++++++-
 fs/9p/vfs_dir.c        |  4 ++--
 fs/9p/vfs_inode.c      | 26 ++------------------------
 fs/9p/vfs_inode_dotl.c |  6 ++----
 4 files changed, 12 insertions(+), 31 deletions(-)

diff --git a/fs/9p/v9fs_vfs.h b/fs/9p/v9fs_vfs.h
index ad0310deb6c8..507dc1389e07 100644
--- a/fs/9p/v9fs_vfs.h
+++ b/fs/9p/v9fs_vfs.h
@@ -43,7 +43,12 @@ void v9fs_free_inode(struct inode *inode);
 int v9fs_init_inode(struct v9fs_session_info *v9ses,
 		    struct inode *inode, umode_t mode, dev_t rdev);
 void v9fs_evict_inode(struct inode *inode);
-ino_t v9fs_qid2ino(struct p9_qid *qid);
+#if (BITS_PER_LONG == 32)
+#define QID2INO(q) ((ino_t) (((q)->path+2) ^ (((q)->path) >> 32)))
+#else
+#define QID2INO(q) ((ino_t) ((q)->path+2))
+#endif
+
 void v9fs_stat2inode(struct p9_wstat *stat, struct inode *inode,
 		      struct super_block *sb, unsigned int flags);
 void v9fs_stat2inode_dotl(struct p9_stat_dotl *stat, struct inode *inode,
diff --git a/fs/9p/vfs_dir.c b/fs/9p/vfs_dir.c
index 4102759a5cb5..e0d34e4e9076 100644
--- a/fs/9p/vfs_dir.c
+++ b/fs/9p/vfs_dir.c
@@ -127,7 +127,7 @@ static int v9fs_dir_readdir(struct file *file, struct dir_context *ctx)
 			}
 
 			over = !dir_emit(ctx, st.name, strlen(st.name),
-					 v9fs_qid2ino(&st.qid), dt_type(&st));
+					QID2INO(&st.qid), dt_type(&st));
 			p9stat_free(&st);
 			if (over)
 				return 0;
@@ -184,7 +184,7 @@ static int v9fs_dir_readdir_dotl(struct file *file, struct dir_context *ctx)
 
 			if (!dir_emit(ctx, curdirent.d_name,
 				      strlen(curdirent.d_name),
-				      v9fs_qid2ino(&curdirent.qid),
+				      QID2INO(&curdirent.qid),
 				      curdirent.d_type))
 				return 0;
 
diff --git a/fs/9p/vfs_inode.c b/fs/9p/vfs_inode.c
index 0d06dca353aa..3b6c9172b40e 100644
--- a/fs/9p/vfs_inode.c
+++ b/fs/9p/vfs_inode.c
@@ -407,7 +407,6 @@ static struct inode *v9fs_qid_iget(struct super_block *sb,
 	dev_t rdev;
 	int retval;
 	umode_t umode;
-	unsigned long i_ino;
 	struct inode *inode;
 	struct v9fs_session_info *v9ses = sb->s_fs_info;
 	int (*test)(struct inode *inode, void *data);
@@ -417,8 +416,7 @@ static struct inode *v9fs_qid_iget(struct super_block *sb,
 	else
 		test = v9fs_test_inode;
 
-	i_ino = v9fs_qid2ino(qid);
-	inode = iget5_locked(sb, i_ino, test, v9fs_set_inode, st);
+	inode = iget5_locked(sb, QID2INO(qid), test, v9fs_set_inode, st);
 	if (!inode)
 		return ERR_PTR(-ENOMEM);
 	if (!(inode->i_state & I_NEW))
@@ -428,7 +426,7 @@ static struct inode *v9fs_qid_iget(struct super_block *sb,
 	 * FIXME!! we may need support for stale inodes
 	 * later.
 	 */
-	inode->i_ino = i_ino;
+	inode->i_ino = QID2INO(qid);
 	umode = p9mode2unixmode(v9ses, st, &rdev);
 	retval = v9fs_init_inode(v9ses, inode, umode, rdev);
 	if (retval)
@@ -1159,26 +1157,6 @@ v9fs_stat2inode(struct p9_wstat *stat, struct inode *inode,
 	v9inode->cache_validity &= ~V9FS_INO_INVALID_ATTR;
 }
 
-/**
- * v9fs_qid2ino - convert qid into inode number
- * @qid: qid to hash
- *
- * BUG: potential for inode number collisions?
- */
-
-ino_t v9fs_qid2ino(struct p9_qid *qid)
-{
-	u64 path = qid->path + 2;
-	ino_t i = 0;
-
-	if (sizeof(ino_t) == sizeof(path))
-		memcpy(&i, &path, sizeof(ino_t));
-	else
-		i = (ino_t) (path ^ (path >> 32));
-
-	return i;
-}
-
 /**
  * v9fs_vfs_get_link - follow a symlink path
  * @dentry: dentry for symlink
diff --git a/fs/9p/vfs_inode_dotl.c b/fs/9p/vfs_inode_dotl.c
index ddc3cfdcc13b..61811cf5d9ff 100644
--- a/fs/9p/vfs_inode_dotl.c
+++ b/fs/9p/vfs_inode_dotl.c
@@ -100,7 +100,6 @@ static struct inode *v9fs_qid_iget_dotl(struct super_block *sb,
 					int new)
 {
 	int retval;
-	unsigned long i_ino;
 	struct inode *inode;
 	struct v9fs_session_info *v9ses = sb->s_fs_info;
 	int (*test)(struct inode *inode, void *data);
@@ -110,8 +109,7 @@ static struct inode *v9fs_qid_iget_dotl(struct super_block *sb,
 	else
 		test = v9fs_test_inode_dotl;
 
-	i_ino = v9fs_qid2ino(qid);
-	inode = iget5_locked(sb, i_ino, test, v9fs_set_inode_dotl, st);
+	inode = iget5_locked(sb, QID2INO(qid), test, v9fs_set_inode_dotl, st);
 	if (!inode)
 		return ERR_PTR(-ENOMEM);
 	if (!(inode->i_state & I_NEW))
@@ -121,7 +119,7 @@ static struct inode *v9fs_qid_iget_dotl(struct super_block *sb,
 	 * FIXME!! we may need support for stale inodes
 	 * later.
 	 */
-	inode->i_ino = i_ino;
+	inode->i_ino = QID2INO(qid);
 	retval = v9fs_init_inode(v9ses, inode,
 				 st->st_mode, new_decode_dev(st->st_rdev));
 	if (retval)

-- 
2.41.0