111 lines
3.0 KiB
Diff
111 lines
3.0 KiB
Diff
From: Jeff Mahoney <jeffm@suse.com>
|
|
Subject: [PATCH] scsi: iterate over devices individually for /proc/scsi/scsi
|
|
References: 263731
|
|
Patch-mainline: Probably never, hch wants to kill /proc/scsi/scsi anyway.
|
|
|
|
On systems with very large numbers (> 1600 or so) of SCSI devices,
|
|
cat /proc/scsi/scsi ends up failing with -ENOMEM. This is due to
|
|
the show routine simply iterating over all of the devices with
|
|
bus_for_each_dev(), and trying to dump all of them into the buffer
|
|
at the same time. On my test system (using scsi_debug with 4064 devices),
|
|
the output ends up being ~ 632k, far more than kmalloc will typically allow.
|
|
|
|
This patch defines its own seq_file opreations to iterate over the scsi
|
|
devices.The result is that each show() operation only dumps ~ 180 bytes
|
|
into the buffer at a time so we don't run out of memory.
|
|
|
|
If the "Attached devices" header isn't required, we can dump the
|
|
sfile->private bit completely.
|
|
|
|
Signed-off-by: Jeff Mahoney <jeffm@suse.com>
|
|
|
|
---
|
|
|
|
drivers/scsi/scsi_proc.c | 58 ++++++++++++++++++++++++++++++++++++++++++-----
|
|
1 file changed, 52 insertions(+), 6 deletions(-)
|
|
|
|
--- a/drivers/scsi/scsi_proc.c
|
|
+++ b/drivers/scsi/scsi_proc.c
|
|
@@ -386,13 +386,59 @@ static ssize_t proc_scsi_write(struct fi
|
|
* @s: output goes here
|
|
* @p: not used
|
|
*/
|
|
-static int proc_scsi_show(struct seq_file *s, void *p)
|
|
+static int always_match(struct device *dev, void *data)
|
|
{
|
|
- seq_printf(s, "Attached devices:\n");
|
|
- bus_for_each_dev(&scsi_bus_type, NULL, s, proc_print_scsidevice);
|
|
- return 0;
|
|
+ return 1;
|
|
}
|
|
|
|
+static inline struct device *next_scsi_device(struct device *start)
|
|
+{
|
|
+ struct device *next = bus_find_device(&scsi_bus_type, start, NULL,
|
|
+ always_match);
|
|
+ put_device(start);
|
|
+ return next;
|
|
+}
|
|
+
|
|
+static void *scsi_seq_start(struct seq_file *sfile, loff_t *pos)
|
|
+{
|
|
+ struct device *dev = NULL;
|
|
+ loff_t n = *pos;
|
|
+
|
|
+ while ((dev = next_scsi_device(dev))) {
|
|
+ if (!n--)
|
|
+ break;
|
|
+ sfile->private++;
|
|
+ }
|
|
+ return dev;
|
|
+}
|
|
+
|
|
+static void *scsi_seq_next(struct seq_file *sfile, void *v, loff_t *pos)
|
|
+{
|
|
+ (*pos)++;
|
|
+ sfile->private++;
|
|
+ return next_scsi_device(v);
|
|
+}
|
|
+
|
|
+static void scsi_seq_stop(struct seq_file *sfile, void *v)
|
|
+{
|
|
+ put_device(v);
|
|
+}
|
|
+
|
|
+static int scsi_seq_show(struct seq_file *sfile, void *dev)
|
|
+{
|
|
+ if (!sfile->private)
|
|
+ seq_puts(sfile, "Attached devices:\n");
|
|
+
|
|
+ return proc_print_scsidevice(dev, sfile);
|
|
+}
|
|
+
|
|
+static struct seq_operations scsi_seq_ops = {
|
|
+ .start = scsi_seq_start,
|
|
+ .next = scsi_seq_next,
|
|
+ .stop = scsi_seq_stop,
|
|
+ .show = scsi_seq_show
|
|
+};
|
|
+
|
|
/**
|
|
* proc_scsi_open - glue function
|
|
* @inode: not used
|
|
@@ -406,7 +452,7 @@ static int proc_scsi_open(struct inode *
|
|
* We don't really need this for the write case but it doesn't
|
|
* harm either.
|
|
*/
|
|
- return single_open(file, proc_scsi_show, NULL);
|
|
+ return seq_open(file, &scsi_seq_ops);
|
|
}
|
|
|
|
static const struct file_operations proc_scsi_operations = {
|
|
@@ -415,7 +461,7 @@ static const struct file_operations proc
|
|
.read = seq_read,
|
|
.write = proc_scsi_write,
|
|
.llseek = seq_lseek,
|
|
- .release = single_release,
|
|
+ .release = seq_release,
|
|
};
|
|
|
|
/**
|