Would the father of init_mem_lth please stand up

Pete Zaitcev
2001-12-08T04:41:15Z

Really someone needs slapping across. What kind of code is that
(in 2.5.1-pre6):

drivers/scsi/sd.c:sd_init()

/* 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, maxparts);
init_mem_lth(sd_gendisks, N_USED_SD_MAJORS);
init_mem_lth(sd_max_sectors, sd_template.dev_max << 4);

if (!rscsi_disks || !sd_sizes || !sd_blocksizes || !sd || !sd_gendisks)
goto cleanup_mem;
#undef init_mem_lth
#undef zero_mem_lth
.....................
cleanup_mem:
kfree(sd_gendisks);
kfree(sd);
kfree(sd_blocksizes);
kfree(sd_sizes);
kfree(rscsi_disks);

However, it's not only about the puking and keyboard cleanups.
The code is buggy as well. Scenario:

0. User inserts a large number of FC-AL adapters with 56 disks each
1. modprobe sd_mod
No SCSI hosts, sd_init() is NOT called.
2. modprobe qla_something
sd_init is called and fails on sd_gendisks. modprobe fails.
sd_sizes, sd_blocksizes, etc. are LEFT DANGLING
3. modprobe qla_something
sd_init is called and fails on sd_sizes.
kfree is called with a bunch of dangling pointers

I stringly urge Linus to drop this so-called "cleanup" from 2.5.1.

No doubt, the existing code was bad. I fixed it somewhat for 2.4,
and am feeding it to Marcelo. I can forward-port that to 2.5
if anyone is interested.

-- Pete