Re: [PATCH] sd-many for 2.4.18-pre7 (uses devfs)

From: Richard Gooch (rgooch@ras.ucalgary.ca)
Date: Mon Jan 28 2002 - 12:25:06 EST


Jens Axboe writes:
> On Mon, Jan 28 2002, Richard Gooch wrote:
> > Jens Axboe writes:
> > > On Sun, Jan 27 2002, Richard Gooch wrote:
> > > > Hi, all. Appended is my sd-many patch. It supports up to 2080
> > > > SD's. This patch is against 2.4.18-pre7, and is essentially the same
> > > > as earlier versions of this patch, just compensating for kernel drift.
> > >
> > > Could you please at least try to follow the style in sd? To me, this
> > > alone is reason enough why the patch should not be applied.
> >
> > ??? I *have* followed the style. Or at least I've tried to. Where did
> > I not?
>
> Are you serious?! You use

Yes, I am. The bits I went and looked over were consistent. I've
scanned over the whole patch and noticed a few places I missed when I
first did the patch. Is the appended patch more to your liking?

                                Regards,

                                        Richard....
Permanent: rgooch@atnf.csiro.au
Current: rgooch@ras.ucalgary.ca

diff -urN linux-2.4.18-pre7/Documentation/Configure.help linux/Documentation/Configure.help
--- linux-2.4.18-pre7/Documentation/Configure.help Sun Jan 27 19:15:28 2002
+++ linux/Documentation/Configure.help Sun Jan 27 19:26:20 2002
@@ -6635,6 +6635,17 @@
   is located on a SCSI disk. In this case, do not compile the driver
   for your SCSI host adapter (below) as a module either.
 
+Many SCSI Discs support
+CONFIG_SD_MANY
+ This allows you to support a very large number of SCSI discs
+ (approximately 2080). You will also need to set CONFIG_DEVFS_FS=y
+ later. This option may consume all unassigned block majors
+ (i.e. those which do not have an allocation in
+ Documentation/devices.txt). Enabling this will consume a few extra
+ kilobytes of kernel memory.
+
+ Unless you have a large storage array, say N.
+
 Maximum number of SCSI disks that can be loaded as modules
 CONFIG_SD_EXTRA_DEVS
   This controls the amount of additional space allocated in tables for
diff -urN linux-2.4.18-pre7/drivers/scsi/Config.in linux/drivers/scsi/Config.in
--- linux-2.4.18-pre7/drivers/scsi/Config.in Sun Jan 27 19:15:32 2002
+++ linux/drivers/scsi/Config.in Sun Jan 27 19:24:07 2002
@@ -3,7 +3,8 @@
 dep_tristate ' SCSI disk support' CONFIG_BLK_DEV_SD $CONFIG_SCSI
 
 if [ "$CONFIG_BLK_DEV_SD" != "n" ]; then
- int 'Maximum number of SCSI disks that can be loaded as modules' CONFIG_SD_EXTRA_DEVS 40
+ bool ' Many (~2080) SCSI discs support (requires devfs)' CONFIG_SD_MANY
+ int ' Maximum number of SCSI disks that can be loaded as modules' CONFIG_SD_EXTRA_DEVS 40
 fi
 
 dep_tristate ' SCSI tape support' CONFIG_CHR_DEV_ST $CONFIG_SCSI
diff -urN linux-2.4.18-pre7/drivers/scsi/hosts.h linux/drivers/scsi/hosts.h
--- linux-2.4.18-pre7/drivers/scsi/hosts.h Sun Jan 27 19:15:32 2002
+++ linux/drivers/scsi/hosts.h Sun Jan 27 19:44:42 2002
@@ -506,9 +506,8 @@
     const char * tag;
     struct module * module; /* Used for loadable modules */
     unsigned char scsi_type;
- unsigned int major;
- unsigned int min_major; /* Minimum major in range. */
- unsigned int max_major; /* Maximum major in range. */
+ unsigned int *majors; /* Array of majors used by driver */
+ unsigned int num_majors; /* Number of majors used by driver */
     unsigned int nr_dev; /* Number currently attached */
     unsigned int dev_noticed; /* Number of devices detected. */
     unsigned int dev_max; /* Current size of arrays */
diff -urN linux-2.4.18-pre7/drivers/scsi/osst.c linux/drivers/scsi/osst.c
--- linux-2.4.18-pre7/drivers/scsi/osst.c Fri Dec 21 10:41:55 2001
+++ linux/drivers/scsi/osst.c Sun Jan 27 19:24:07 2002
@@ -162,7 +162,6 @@
        name: "OnStream tape",
        tag: "osst",
        scsi_type: TYPE_TAPE,
- major: OSST_MAJOR,
        detect: osst_detect,
        init: osst_init,
        attach: osst_attach,
diff -urN linux-2.4.18-pre7/drivers/scsi/scsi_lib.c linux/drivers/scsi/scsi_lib.c
--- linux-2.4.18-pre7/drivers/scsi/scsi_lib.c Fri Oct 12 16:35:54 2001
+++ linux/drivers/scsi/scsi_lib.c Mon Jan 28 10:18:10 2002
@@ -795,25 +795,12 @@
                  * Search for a block device driver that supports this
                  * major.
                  */
- if (spnt->blk && spnt->major == major) {
- return spnt;
- }
- /*
- * I am still not entirely satisfied with this solution,
- * but it is good enough for now. Disks have a number of
- * major numbers associated with them, the primary
- * 8, which we test above, and a secondary range of 7
- * different consecutive major numbers. If this ever
- * becomes insufficient, then we could add another function
- * to the structure, and generalize this completely.
- */
- if( spnt->min_major != 0
- && spnt->max_major != 0
- && major >= spnt->min_major
- && major <= spnt->max_major )
- {
- return spnt;
- }
+ int i;
+ if (!spnt->blk || !spnt->majors)
+ continue;
+ for (i = 0; i < spnt->num_majors; ++i)
+ if (spnt->majors[i] == major)
+ return spnt;
         }
         return NULL;
 }
diff -urN linux-2.4.18-pre7/drivers/scsi/sd.c linux/drivers/scsi/sd.c
--- linux-2.4.18-pre7/drivers/scsi/sd.c Sun Jan 27 19:15:32 2002
+++ linux/drivers/scsi/sd.c Mon Jan 28 10:21:14 2002
@@ -28,6 +28,8 @@
  *
  * Modified by Alex Davis <letmein@erols.com>
  * Fix problem where removable media could be ejected after sd_open.
+ *
+ * Modified by Richard Gooch rgooch@atnf.csiro.au to support >128 discs.
  */
 
 #include <linux/config.h>
@@ -65,7 +67,11 @@
  * static const char RCSid[] = "$Header:";
  */
 
+#ifdef CONFIG_SD_MANY
+#define SD_MAJOR(i) sd_template.majors[(i)]
+#else
 #define SD_MAJOR(i) (!(i) ? SCSI_DISK0_MAJOR : SCSI_DISK1_MAJOR-1+(i))
+#endif
 
 #define SCSI_DISKS_PER_MAJOR 16
 #define SD_MAJOR_NUMBER(i) SD_MAJOR((i) >> 8)
@@ -77,6 +83,14 @@
 
 #define MAX_RETRIES 5
 
+#ifdef CONFIG_SD_MANY
+#define sdmalloc(size) vmalloc((size))
+#define sdfree(ptr) vfree((ptr))
+#else
+#define sdmalloc(size) kmalloc((size),GFP_ATOMIC)
+#define sdfree(ptr) kfree((ptr))
+#endif
+
 /*
  * Time out in seconds for disks and Magneto-opticals (which are slower).
  */
@@ -109,12 +123,6 @@
         name:"disk",
         tag:"sd",
         scsi_type:TYPE_DISK,
- major:SCSI_DISK0_MAJOR,
- /*
- * Secondary range of majors that this driver handles.
- */
- min_major:SCSI_DISK1_MAJOR,
- max_major:SCSI_DISK7_MAJOR,
         blk:1,
         detect:sd_detect,
         init:sd_init,
@@ -124,6 +132,19 @@
         init_command:sd_init_command,
 };
 
+#ifdef CONFIG_SD_MANY
+static inline int sd_devnum_to_index(int devnum)
+{
+ int i, major = MAJOR (devnum);
+
+ for (i = 0; i < sd_template.num_majors; ++i) {
+ if (sd_template.majors[i] != major)
+ continue;
+ return (i << 4) | (MINOR (devnum) >> 4);
+ }
+ return -ENODEV;
+}
+#endif
 
 static void rw_intr(Scsi_Cmnd * SCpnt);
 
@@ -1054,6 +1075,43 @@
         return i;
 }
 
+static int sd_alloc_majors(void)
+/* Allocate as many majors as required
+ */
+{
+ int i, major;
+
+ if ( ( sd_template.majors =
+ kmalloc(sizeof *sd_template.majors * N_USED_SD_MAJORS,
+ GFP_KERNEL) ) == NULL ) {
+ printk("sd.c: unable to allocate major array\n");
+ return -ENOMEM;
+ }
+ sd_template.majors[0] = SCSI_DISK0_MAJOR;
+ for (i = 1; (i < N_USED_SD_MAJORS) && (i <N_SD_PREASSIGNED_MAJORS);++i)
+ sd_template.majors[i] = SCSI_DISK1_MAJOR + i - 1;
+ for (; (i >= N_SD_PREASSIGNED_MAJORS) && (i < N_USED_SD_MAJORS); ++i) {
+ if ( ( major = devfs_alloc_major(DEVFS_SPECIAL_BLK) ) < 0 ) {
+ printk(KERN_WARNING __FUNCTION__ "() major[%d] allocation failed\n", i);
+ break;
+ }
+ sd_template.majors[i] = major;
+ }
+ sd_template.dev_max = i * SCSI_DISKS_PER_MAJOR;
+ sd_template.num_majors = i;
+ return 0;
+} /* End Function sd_alloc_majors */
+
+static void sd_dealloc_majors(void)
+/* Deallocate all the allocated majors
+ */
+{
+ int i;
+
+ for (i = sd_template.num_majors - 1; i >= N_SD_PREASSIGNED_MAJORS; --i)
+ devfs_dealloc_major(DEVFS_SPECIAL_BLK, sd_template.majors[i]);
+} /* End Function sd_dealloc_majors */
+
 /*
  * The sd_init() function looks at all SCSI drives present, determines
  * their size, and reads partition table entries for them.
@@ -1068,17 +1126,22 @@
         if (sd_template.dev_noticed == 0)
                 return 0;
 
- if (!rscsi_disks)
+ if (!rscsi_disks) {
+ if ( in_interrupt() ) {
+ printk (__FUNCTION__ "(): called from interrupt\n");
+ return 1;
+ }
                 sd_template.dev_max = sd_template.dev_noticed + SD_EXTRA_DEVS;
-
- if (sd_template.dev_max > N_SD_MAJORS * SCSI_DISKS_PER_MAJOR)
- sd_template.dev_max = N_SD_MAJORS * SCSI_DISKS_PER_MAJOR;
+ if ( sd_alloc_majors() )
+ return 1;
+ }
 
         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));
                                 sd_template.dev_noticed = 0;
+ sd_dealloc_majors();
                                 return 1;
                         }
                 }
@@ -1088,26 +1151,26 @@
         if (rscsi_disks)
                 return 0;
 
- rscsi_disks = kmalloc(sd_template.dev_max * sizeof(Scsi_Disk), GFP_ATOMIC);
+ rscsi_disks = sdmalloc(sd_template.dev_max * sizeof(Scsi_Disk));
         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);
+ sd_sizes = sdmalloc((sd_template.dev_max << 4) * sizeof(int));
         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);
+ sd_blocksizes = sdmalloc((sd_template.dev_max << 4) * sizeof(int));
         if (!sd_blocksizes)
                 goto cleanup_sizes;
         
- sd_hardsizes = kmalloc((sd_template.dev_max << 4) * sizeof(int), GFP_ATOMIC);
+ sd_hardsizes = sdmalloc((sd_template.dev_max << 4) * sizeof(int));
         if (!sd_hardsizes)
                 goto cleanup_blocksizes;
 
- sd_max_sectors = kmalloc((sd_template.dev_max << 4) * sizeof(int), GFP_ATOMIC);
+ sd_max_sectors = sdmalloc((sd_template.dev_max << 4) * sizeof(int));
         if (!sd_max_sectors)
                 goto cleanup_max_sectors;
 
@@ -1131,9 +1194,7 @@
          * FIXME: should unregister blksize_size, hardsect_size and max_sectors when
          * the module is unloaded.
          */
- sd = kmalloc((sd_template.dev_max << 4) *
- sizeof(struct hd_struct),
- GFP_ATOMIC);
+ sd = sdmalloc((sd_template.dev_max << 4) * sizeof(struct hd_struct));
         if (!sd)
                 goto cleanup_sd;
         memset(sd, 0, (sd_template.dev_max << 4) * sizeof(struct hd_struct));
@@ -1179,17 +1240,17 @@
         if (sd_gendisks != &sd_gendisk)
                 kfree(sd_gendisks);
 cleanup_sd_gendisks:
- kfree(sd);
+ sdfree(sd);
 cleanup_sd:
- kfree(sd_max_sectors);
+ sdfree(sd_max_sectors);
 cleanup_max_sectors:
- kfree(sd_hardsizes);
+ sdfree(sd_hardsizes);
 cleanup_blocksizes:
- kfree(sd_blocksizes);
+ sdfree(sd_blocksizes);
 cleanup_sizes:
- kfree(sd_sizes);
+ sdfree(sd_sizes);
 cleanup_disks:
- kfree(rscsi_disks);
+ sdfree(rscsi_disks);
         rscsi_disks = NULL;
 cleanup_devfs:
         for (i = 0; i < N_USED_SD_MAJORS; i++) {
@@ -1197,6 +1258,7 @@
         }
         sd_registered--;
         sd_template.dev_noticed = 0;
+ sd_dealloc_majors();
         return 1;
 }
 
@@ -1402,16 +1464,17 @@
 
         scsi_unregister_module(MODULE_SCSI_DEV, &sd_template);
 
+ sd_dealloc_majors();
         for (i = 0; i < N_USED_SD_MAJORS; i++)
                 devfs_unregister_blkdev(SD_MAJOR(i), "sd");
 
         sd_registered--;
         if (rscsi_disks != NULL) {
- kfree(rscsi_disks);
- kfree(sd_sizes);
- kfree(sd_blocksizes);
- kfree(sd_hardsizes);
- kfree((char *) sd);
+ sdfree(rscsi_disks);
+ sdfree(sd_sizes);
+ sdfree(sd_blocksizes);
+ sdfree(sd_hardsizes);
+ sdfree((char *) sd);
         }
         for (i = 0; i < N_USED_SD_MAJORS; i++) {
                 del_gendisk(&sd_gendisks[i]);
diff -urN linux-2.4.18-pre7/drivers/scsi/sd.h linux/drivers/scsi/sd.h
--- linux-2.4.18-pre7/drivers/scsi/sd.h Tue Jan 22 22:29:31 2002
+++ linux/drivers/scsi/sd.h Sun Jan 27 19:44:42 2002
@@ -42,10 +42,14 @@
  */
 extern kdev_t sd_find_target(void *host, int tgt);
 
-#define N_SD_MAJORS 8
+#define N_SD_PREASSIGNED_MAJORS 8
 
-#define SD_MAJOR_MASK (N_SD_MAJORS - 1)
+#ifdef CONFIG_SD_MANY
+#define SD_PARTITION(i) ((sd_devnum_to_index((i)) << 4) | ((i)&0x0f))
+#else
+#define SD_MAJOR_MASK (N_SD_PREASSIGNED_MAJORS - 1)
 #define SD_PARTITION(i) (((MAJOR(i) & SD_MAJOR_MASK) << 8) | (MINOR(i) & 255))
+#endif
 
 #endif
 
diff -urN linux-2.4.18-pre7/drivers/scsi/sg.c linux/drivers/scsi/sg.c
--- linux-2.4.18-pre7/drivers/scsi/sg.c Sun Jan 27 19:15:33 2002
+++ linux/drivers/scsi/sg.c Sun Jan 27 19:24:07 2002
@@ -125,7 +125,6 @@
 {
       tag:"sg",
       scsi_type:0xff,
- major:SCSI_GENERIC_MAJOR,
       detect:sg_detect,
       init:sg_init,
       finish:sg_finish,
diff -urN linux-2.4.18-pre7/drivers/scsi/sr.c linux/drivers/scsi/sr.c
--- linux-2.4.18-pre7/drivers/scsi/sr.c Sun Jan 27 19:15:33 2002
+++ linux/drivers/scsi/sr.c Sun Jan 27 19:24:07 2002
@@ -69,12 +69,15 @@
 
 static int sr_init_command(Scsi_Cmnd *);
 
+static unsigned int sr_major = SCSI_CDROM_MAJOR;
+
 static struct Scsi_Device_Template sr_template =
 {
         name:"cdrom",
         tag:"sr",
         scsi_type:TYPE_ROM,
- major:SCSI_CDROM_MAJOR,
+ majors:&sr_major,
+ num_majors:1,
         blk:1,
         detect:sr_detect,
         init:sr_init,
diff -urN linux-2.4.18-pre7/drivers/scsi/st.c linux/drivers/scsi/st.c
--- linux-2.4.18-pre7/drivers/scsi/st.c Sun Jan 27 19:15:33 2002
+++ linux/drivers/scsi/st.c Sun Jan 27 19:24:07 2002
@@ -170,7 +170,6 @@
         name:"tape",
         tag:"st",
         scsi_type:TYPE_TAPE,
- major:SCSI_TAPE_MAJOR,
         detect:st_detect,
         init:st_init,
         attach:st_attach,
diff -urN linux-2.4.18-pre7/include/linux/blk.h linux/include/linux/blk.h
--- linux-2.4.18-pre7/include/linux/blk.h Tue Jan 22 22:29:11 2002
+++ linux/include/linux/blk.h Sun Jan 27 19:44:21 2002
@@ -146,7 +146,11 @@
 
 #define DEVICE_NAME "scsidisk"
 #define TIMEOUT_VALUE (2*HZ)
+#ifdef CONFIG_SD_MANY
+#define DEVICE_NR(device) sd_devnum_to_index((device))
+#else
 #define DEVICE_NR(device) (((MAJOR(device) & SD_MAJOR_MASK) << (8 - 4)) + (MINOR(device) >> 4))
+#endif
 
 /* Kludge to use the same number for both char and block major numbers */
 #elif (MAJOR_NR == MD_MAJOR) && defined(MD_DRIVER)
-
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