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Subject[PATCH] sd_init
Moving the "partition shift"
block += partition_start;
from the bowels of SCSI and IDE drivers to ll_rw_blk.c
(something that must wait for 2.5) I changed sd_init a bit
and noticed that the present version is buggy:

static struct gendisk sd_gendisk = {
SCSI_DISK0_MAJOR, /* Major number */
...
};
static struct gendisk *sd_gendisks = &sd_gendisk;
...
static int sd_init() {
...
if (N_USED_SD_MAJORS > 1)
sd_gendisks = kmalloc(N_USED_SD_MAJORS * sizeof(struct gendisk), GFP_ATOMIC);
...
sd_gendisks[i].de_arr = kmalloc(...);
if (!sd_gendisks[i].de_arr)
goto cleanup_gendisks_de_arr;
...
cleanup_gendisks_de_arr:
...
kfree(sd_gendisks);


That is, we may free sd_gendisk that was never allocated.
The easiest fix is to delete the condition "if (N_USED_SD_MAJORS > 1)".

Andries


(I was allocating some more stuff there, and following the local style
gave too ugly code. Present version of this one-line fix follows.)

diff -u --recursive --new-file ../linux-2.4.6-pre3/linux/drivers/scsi/sd.c ./linux/drivers/scsi/sd.c
--- ../linux-2.4.6-pre3/linux/drivers/scsi/sd.c Wed Jun 13 09:21:03 2001
+++ ./linux/drivers/scsi/sd.c Mon Jun 18 00:52:18 2001
@@ -55,9 +55,6 @@

#include <linux/genhd.h>

-/*
- * static const char RCSid[] = "$Header:";
- */

#define SD_MAJOR(i) (!(i) ? SCSI_DISK0_MAJOR : SCSI_DISK1_MAJOR-1+(i))

@@ -66,8 +63,7 @@
#define SD_MINOR_NUMBER(i) ((i) & 255)
#define MKDEV_SD_PARTITION(i) MKDEV(SD_MAJOR_NUMBER(i), (i) & 255)
#define MKDEV_SD(index) MKDEV_SD_PARTITION((index) << 4)
-#define N_USED_SCSI_DISKS (sd_template.dev_max + SCSI_DISKS_PER_MAJOR - 1)
-#define N_USED_SD_MAJORS (N_USED_SCSI_DISKS / SCSI_DISKS_PER_MAJOR)
+#define N_USED_SD_MAJORS (1 + ((sd_template.dev_max - 1) >> 4))

#define MAX_RETRIES 5

@@ -90,7 +86,6 @@

static int sd_init_onedisk(int);

-
static int sd_init(void);
static void sd_finish(void);
static int sd_attach(Scsi_Device *);
@@ -1020,7 +1015,7 @@

static int sd_init()
{
- int i;
+ int i, maxparts;

if (sd_template.dev_noticed == 0)
return 0;
@@ -1031,37 +1026,44 @@
if (sd_template.dev_max > N_SD_MAJORS * SCSI_DISKS_PER_MAJOR)
sd_template.dev_max = N_SD_MAJORS * SCSI_DISKS_PER_MAJOR;

+ /* At most 16 partitions on each scsi disk. */
+ maxparts = (sd_template.dev_max << 4);
+ if (maxparts == 0)
+ return 0;
+
if (!sd_registered) {
for (i = 0; i < N_USED_SD_MAJORS; i++) {
if (devfs_register_blkdev(SD_MAJOR(i), "sd", &sd_fops)) {
- printk("Unable to get major %d for SCSI disk\n", SD_MAJOR(i));
+ printk("Unable to get major %d for SCSI disk\n",
+ SD_MAJOR(i));
return 1;
}
}
sd_registered++;
}
+
/* We do not support attaching loadable devices yet. */
if (rscsi_disks)
return 0;

- rscsi_disks = kmalloc(sd_template.dev_max * sizeof(Scsi_Disk), GFP_ATOMIC);
- if (!rscsi_disks)
- goto cleanup_devfs;
- memset(rscsi_disks, 0, sd_template.dev_max * sizeof(Scsi_Disk));
-
- /* for every (necessary) major: */
- sd_sizes = kmalloc((sd_template.dev_max << 4) * sizeof(int), GFP_ATOMIC);
- if (!sd_sizes)
- goto cleanup_disks;
- memset(sd_sizes, 0, (sd_template.dev_max << 4) * sizeof(int));
-
- sd_blocksizes = kmalloc((sd_template.dev_max << 4) * sizeof(int), GFP_ATOMIC);
- if (!sd_blocksizes)
- goto cleanup_sizes;
-
- sd_hardsizes = kmalloc((sd_template.dev_max << 4) * sizeof(int), GFP_ATOMIC);
- if (!sd_hardsizes)
- goto cleanup_blocksizes;
+ /* Allocate memory */
+#define init_mem_lth(x,n) x = kmalloc((n) * sizeof(*x), GFP_ATOMIC)
+#define zero_mem_lth(x,n) memset(x, 0, (n) * sizeof(*x))
+
+ init_mem_lth(rscsi_disks, sd_template.dev_max);
+ init_mem_lth(sd_sizes, maxparts);
+ init_mem_lth(sd_blocksizes, maxparts);
+ init_mem_lth(sd_hardsizes, maxparts);
+ init_mem_lth(sd, maxparts);
+ init_mem_lth(sd_gendisks, N_USED_SD_MAJORS);
+
+ if (!rscsi_disks || !sd_sizes || !sd_blocksizes ||
+ !sd_hardsizes || !sd || !sd_gendisks)
+ goto cleanup_mem;
+
+ zero_mem_lth(rscsi_disks, sd_template.dev_max);
+ zero_mem_lth(sd_sizes, maxparts);
+ zero_mem_lth(sd, maxparts);

for (i = 0; i < sd_template.dev_max << 4; i++) {
sd_blocksizes[i] = 1024;
@@ -1069,68 +1071,59 @@
}

for (i = 0; i < N_USED_SD_MAJORS; i++) {
- blksize_size[SD_MAJOR(i)] = sd_blocksizes + i * (SCSI_DISKS_PER_MAJOR << 4);
- hardsect_size[SD_MAJOR(i)] = sd_hardsizes + i * (SCSI_DISKS_PER_MAJOR << 4);
+ int parts_per_major = (SCSI_DISKS_PER_MAJOR << 4);
+
+ blksize_size[SD_MAJOR(i)] =
+ sd_blocksizes + i * parts_per_major;
+ hardsect_size[SD_MAJOR(i)] =
+ sd_hardsizes + i * parts_per_major;
}
- sd = kmalloc((sd_template.dev_max << 4) *
- sizeof(struct hd_struct),
- GFP_ATOMIC);
- if (!sd)
- goto cleanup_sd;
- memset(sd, 0, (sd_template.dev_max << 4) * sizeof(struct hd_struct));
-
- if (N_USED_SD_MAJORS > 1)
- sd_gendisks = kmalloc(N_USED_SD_MAJORS * sizeof(struct gendisk), GFP_ATOMIC);
- if (!sd_gendisks)
- goto cleanup_sd_gendisks;
+
for (i = 0; i < N_USED_SD_MAJORS; i++) {
+ int N = SCSI_DISKS_PER_MAJOR;
+
sd_gendisks[i] = sd_gendisk;
- sd_gendisks[i].de_arr = kmalloc (SCSI_DISKS_PER_MAJOR * sizeof *sd_gendisks[i].de_arr,
- GFP_ATOMIC);
- if (!sd_gendisks[i].de_arr)
- goto cleanup_gendisks_de_arr;
- memset (sd_gendisks[i].de_arr, 0,
- SCSI_DISKS_PER_MAJOR * sizeof *sd_gendisks[i].de_arr);
- sd_gendisks[i].flags = kmalloc (SCSI_DISKS_PER_MAJOR * sizeof *sd_gendisks[i].flags,
- GFP_ATOMIC);
- if (!sd_gendisks[i].flags)
- goto cleanup_gendisks_flags;
- memset (sd_gendisks[i].flags, 0,
- SCSI_DISKS_PER_MAJOR * sizeof *sd_gendisks[i].flags);
+
+ init_mem_lth(sd_gendisks[i].de_arr, N);
+ init_mem_lth(sd_gendisks[i].flags, N);
+
+ if (!sd_gendisks[i].de_arr || !sd_gendisks[i].flags)
+ goto cleanup_gendisks;
+
+ zero_mem_lth(sd_gendisks[i].de_arr, N);
+ zero_mem_lth(sd_gendisks[i].flags, N);
+
sd_gendisks[i].major = SD_MAJOR(i);
sd_gendisks[i].major_name = "sd";
sd_gendisks[i].minor_shift = 4;
sd_gendisks[i].max_p = 1 << 4;
- sd_gendisks[i].part = sd + (i * SCSI_DISKS_PER_MAJOR << 4);
- sd_gendisks[i].sizes = sd_sizes + (i * SCSI_DISKS_PER_MAJOR << 4);
+ sd_gendisks[i].part = sd + i * (N << 4);
+ sd_gendisks[i].sizes = sd_sizes + i * (N << 4);
sd_gendisks[i].nr_real = 0;
sd_gendisks[i].next = sd_gendisks + i + 1;
- sd_gendisks[i].real_devices =
- (void *) (rscsi_disks + i * SCSI_DISKS_PER_MAJOR);
+ sd_gendisks[i].real_devices = (void *) (rscsi_disks + i * N);
}
+#undef init_mem_lth
+#undef zero_mem_lth

LAST_SD_GENDISK.next = NULL;
return 0;

-cleanup_gendisks_flags:
- kfree(sd_gendisks[i].de_arr);
-cleanup_gendisks_de_arr:
- while (--i >= 0 ) {
+cleanup_gendisks:
+ /* kfree can handle NULL, so no test is required here */
+ for (i = 0; i < N_USED_SD_MAJORS; i++) {
kfree(sd_gendisks[i].de_arr);
kfree(sd_gendisks[i].flags);
}
kfree(sd_gendisks);
-cleanup_sd_gendisks:
+cleanup_mem:
+ /* kfree can handle NULL, so no test is required here */
kfree(sd);
-cleanup_sd:
kfree(sd_hardsizes);
-cleanup_blocksizes:
kfree(sd_blocksizes);
-cleanup_sizes:
kfree(sd_sizes);
-cleanup_disks:
kfree(rscsi_disks);
-cleanup_devfs:
+
for (i = 0; i < N_USED_SD_MAJORS; i++) {
devfs_unregister_blkdev(SD_MAJOR(i), "sd");
}
-
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