Use sysfs attribute files to get the long value of zoned device
information.

Signed-off-by: Sam Li <faithilikerun@gmail.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
---
 block/file-posix.c | 37 +++++++++++++++++++++++--------------
 1 file changed, 23 insertions(+), 14 deletions(-)

diff --git a/block/file-posix.c b/block/file-posix.c
index 48cd096624..a40eab64a2 100644
--- a/block/file-posix.c
+++ b/block/file-posix.c
@@ -1210,29 +1210,27 @@ static int hdev_get_max_hw_transfer(int fd, struct stat *st)
 #endif
 }
 
-static int hdev_get_max_segments(int fd, struct stat *st)
-{
+/*
+ * Get zoned device information (chunk_sectors, zoned_append_max_bytes,
+ * max_open_zones, max_active_zones) through sysfs attribute files.
+ */
+static long get_sysfs_long_val(int fd, struct stat *st,
+                               const char *attribute) {
 #ifdef CONFIG_LINUX
     char buf[32];
     const char *end;
     char *sysfspath = NULL;
     int ret;
     int sysfd = -1;
-    long max_segments;
-
-    if (S_ISCHR(st->st_mode)) {
-        if (ioctl(fd, SG_GET_SG_TABLESIZE, &ret) == 0) {
-            return ret;
-        }
-        return -ENOTSUP;
-    }
+    long val;
 
     if (!S_ISBLK(st->st_mode)) {
         return -ENOTSUP;
     }
 
-    sysfspath = g_strdup_printf("/sys/dev/block/%u:%u/queue/max_segments",
-                                major(st->st_rdev), minor(st->st_rdev));
+    sysfspath = g_strdup_printf("/sys/dev/block/%u:%u/queue/%s",
+                                major(st->st_rdev), minor(st->st_rdev),
+                                attribute);
     sysfd = open(sysfspath, O_RDONLY);
     if (sysfd == -1) {
         ret = -errno;
@@ -1250,9 +1248,9 @@ static int hdev_get_max_segments(int fd, struct stat *st)
     }
     buf[ret] = 0;
     /* The file is ended with '\n', pass 'end' to accept that. */
-    ret = qemu_strtol(buf, &end, 10, &max_segments);
+    ret = qemu_strtol(buf, &end, 10, &val);
     if (ret == 0 && end && *end == '\n') {
-        ret = max_segments;
+        ret = val;
     }
 
 out:
@@ -1266,6 +1264,17 @@ out:
 #endif
 }
 
+static int hdev_get_max_segments(int fd, struct stat *st) {
+    int ret;
+    if (S_ISCHR(st->st_mode)) {
+        if (ioctl(fd, SG_GET_SG_TABLESIZE, &ret) == 0) {
+            return ret;
+        }
+        return -ENOTSUP;
+    }
+    return get_sysfs_long_val(fd, st, "max_segments");
+}
+
 static void raw_refresh_limits(BlockDriverState *bs, Error **errp)
 {
     BDRVRawState *s = bs->opaque;
-- 
2.37.1

On Fri, Aug 05, 2022 at 03:57:45PM +0800, Sam Li wrote:
> Use sysfs attribute files to get the long value of zoned device
> information.
> 
> Signed-off-by: Sam Li <faithilikerun@gmail.com>
> Reviewed-by: Hannes Reinecke <hare@suse.de>
> ---
>  block/file-posix.c | 37 +++++++++++++++++++++++--------------
>  1 file changed, 23 insertions(+), 14 deletions(-)
> 
> diff --git a/block/file-posix.c b/block/file-posix.c
> index 48cd096624..a40eab64a2 100644
> --- a/block/file-posix.c
> +++ b/block/file-posix.c
> @@ -1210,29 +1210,27 @@ static int hdev_get_max_hw_transfer(int fd, struct stat *st)
>  #endif
>  }
>  
> -static int hdev_get_max_segments(int fd, struct stat *st)
> -{
> +/*
> + * Get zoned device information (chunk_sectors, zoned_append_max_bytes,
> + * max_open_zones, max_active_zones) through sysfs attribute files.
> + */
> +static long get_sysfs_long_val(int fd, struct stat *st,
> +                               const char *attribute) {

Is the fd argument used or can it be removed?

Other than that:

Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>

Stefan Hajnoczi <stefanha@redhat.com> 于2022年8月8日周一 21:52写道：
>
> On Fri, Aug 05, 2022 at 03:57:45PM +0800, Sam Li wrote:
> > Use sysfs attribute files to get the long value of zoned device
> > information.
> >
> > Signed-off-by: Sam Li <faithilikerun@gmail.com>
> > Reviewed-by: Hannes Reinecke <hare@suse.de>
> > ---
> >  block/file-posix.c | 37 +++++++++++++++++++++++--------------
> >  1 file changed, 23 insertions(+), 14 deletions(-)
> >
> > diff --git a/block/file-posix.c b/block/file-posix.c
> > index 48cd096624..a40eab64a2 100644
> > --- a/block/file-posix.c
> > +++ b/block/file-posix.c
> > @@ -1210,29 +1210,27 @@ static int hdev_get_max_hw_transfer(int fd, struct stat *st)
> >  #endif
> >  }
> >
> > -static int hdev_get_max_segments(int fd, struct stat *st)
> > -{
> > +/*
> > + * Get zoned device information (chunk_sectors, zoned_append_max_bytes,
> > + * max_open_zones, max_active_zones) through sysfs attribute files.
> > + */
> > +static long get_sysfs_long_val(int fd, struct stat *st,
> > +                               const char *attribute) {
>
> Is the fd argument used or can it be removed?

Yes, it can be removed.