From: Joanne Koong <joannelkoong@gmail.com>
Date: Fri, 27 Sep 2024 00:33:39 +0000 (-0700)
Subject: Change FUSE_MAX_MAX_PAGES to FUSE_DEFAULT_MAX_PAGES_LIMIT
X-Git-Tag: fuse-3.17.1-rc0~66
X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=9069ad9eb6ba908de9cbbdd8ba411cac963101ff;p=qemu-gpiodev%2Flibfuse.git

Change FUSE_MAX_MAX_PAGES to FUSE_DEFAULT_MAX_PAGES_LIMIT

A recent upstream patch [1] changed FUSE_MAX_MAX_PAGES to
FUSE_DEFAULT_MAX_PAGES_LIMIT.

Update libfuse to use FUSE_DEFAULT_MAX_PAGES_LIMIT as well
instead of FUSE_MAX_MAX_PAGES.

[1] https://lore.kernel.org/linux-fsdevel/20240923171311.1561917-1-joannelkoong@gmail.com/T/#t
---

diff --git a/lib/fuse_i.h b/lib/fuse_i.h
index 1519ce0..2815a8a 100644
--- a/lib/fuse_i.h
+++ b/lib/fuse_i.h
@@ -196,7 +196,13 @@ int fuse_session_loop_mt_312(struct fuse_session *se, struct fuse_loop_config *c
 int fuse_loop_cfg_verify(struct fuse_loop_config *config);
 
 
-#define FUSE_MAX_MAX_PAGES 256
+/*
+ * This can be changed dynamically on recent kernels through the
+ * /proc/sys/fs/fuse/max_pages_limit interface.
+ *
+ * Older kernels will always use the default value.
+ */
+#define FUSE_DEFAULT_MAX_PAGES_LIMIT 256
 #define FUSE_DEFAULT_MAX_PAGES_PER_REQ 32
 
 /* room needed in buffer to accommodate header */
diff --git a/lib/fuse_lowlevel.c b/lib/fuse_lowlevel.c
index 824dbab..819e435 100644
--- a/lib/fuse_lowlevel.c
+++ b/lib/fuse_lowlevel.c
@@ -2915,19 +2915,19 @@ static unsigned int get_max_pages(void)
 
 	fd = open("/proc/sys/fs/fuse/max_pages_limit", O_RDONLY);
 	if (fd < 0)
-		return FUSE_MAX_MAX_PAGES;
+		return FUSE_DEFAULT_MAX_PAGES_LIMIT;
 
 	res = read(fd, buf, sizeof(buf) - 1);
 
 	close(fd);
 
 	if (res < 0)
-		return FUSE_MAX_MAX_PAGES;
+		return FUSE_DEFAULT_MAX_PAGES_LIMIT;
 
 	buf[res] = '\0';
 
 	res = strtol(buf, NULL, 10);
-	return res < 0 ? FUSE_MAX_MAX_PAGES : res;
+	return res < 0 ? FUSE_DEFAULT_MAX_PAGES_LIMIT : res;
 }
 
 int fuse_session_receive_buf(struct fuse_session *se, struct fuse_buf *buf)