From: "Ewan D. Milne" <emilne@xxxxxxxxxx>
This prevents crashing due to accessing a removed element on the list,
the iterator will now hold the correct reference. It was not sufficient
to rely on the klist's reference on the containing device object.
>From a patch originally developed by David Jeffery <djeffery@xxxxxxxxxx>
Signed-off-by: Ewan D. Milne <emilne@xxxxxxxxxx>
---
drivers/scsi/scsi_proc.c | 49 ++++++++++++++++++++++++++++--------------------
1 file changed, 29 insertions(+), 20 deletions(-)
diff --git a/drivers/scsi/scsi_proc.c b/drivers/scsi/scsi_proc.c
index 251598e..6c1b79d 100644
--- a/drivers/scsi/scsi_proc.c
+++ b/drivers/scsi/scsi_proc.c
@@ -40,6 +40,11 @@
/* 4K page size, but our output routines, use some slack for overruns */
#define PROC_BLOCK_SIZE (3*1024)
+struct scsi_proc_state {
+ struct klist_iter iter;
+ int pos;
+};
+
static struct proc_dir_entry *proc_scsi;
/* Protect sht->present and sht->proc_dir */
@@ -370,47 +375,50 @@ static ssize_t proc_scsi_write(struct file *file, const char __user *buf,
return err;
}
-static int always_match(struct device *dev, void *data)
-{
- 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 scsi_proc_state *state = sfile->private;
struct device *dev = NULL;
loff_t n = *pos;
+ int err;
+
+ err = bus_device_iter_init(&state->iter, &scsi_bus_type);
+ if (err < 0)
+ return ERR_PTR(err);
- while ((dev = next_scsi_device(dev))) {
+ while ((dev = bus_device_iter_next(&state->iter))) {
if (!n--)
break;
- sfile->private++;
+ put_device(dev);
+ state->pos++;
}
return dev;
}
static void *scsi_seq_next(struct seq_file *sfile, void *v, loff_t *pos)
{
+ struct scsi_proc_state *state = sfile->private;
+
(*pos)++;
- sfile->private++;
- return next_scsi_device(v);
+ put_device(v);
+ state->pos++;
+
+ return bus_device_iter_next(&state->iter);
}
static void scsi_seq_stop(struct seq_file *sfile, void *v)
{
+ struct scsi_proc_state *state = sfile->private;
+
put_device(v);
+ bus_device_iter_exit(&state->iter);
}
static int scsi_seq_show(struct seq_file *sfile, void *dev)
{
- if (!sfile->private)
+ struct scsi_proc_state *state = sfile->private;
+
+ if (!state->pos)
seq_puts(sfile, "Attached devices:\n");
return proc_print_scsidevice(dev, sfile);
@@ -436,7 +444,8 @@ static int proc_scsi_open(struct inode *inode, struct file *file)
* We don't really need this for the write case but it doesn't
* harm either.
*/
- return seq_open(file, &scsi_seq_ops);
+ return seq_open_private(file, &scsi_seq_ops,
+ sizeof(struct scsi_proc_state));
}
static const struct file_operations proc_scsi_operations = {
@@ -445,7 +454,7 @@ static const struct file_operations proc_scsi_operations = {
.read = seq_read,
.write = proc_scsi_write,
.llseek = seq_lseek,
- .release = seq_release,
+ .release = seq_release_private,
};
/**
--
2.1.0
--
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