Hello, Harry.
On 04/22/2010 12:15 PM, Harry Zhang wrote:
> + /* Since EM buffer is in ABAR, commonly, the buffer size should be
> + * less than a page. Check buffer size against PAGE_SIZE in case of
> + * some rare instance. Only transfer the first page in this case.
> + */
Oh, the PAGE_SIZE limit comes from the way sysfs attributes are
implemented. The kernel buffer sysfs uses is PAGE_SIZE so
reads/writes can't be larger than that. If you write past PAGE_SIZE
from show, you'll corrupt someone else's memory.
> + if (count > PAGE_SIZE) {
> + dev_printk(KERN_WARNING, dev,
> + "EM read buffer size %u is larger than %lu",
> + hpriv->em_buf_sz, PAGE_SIZE);
> + count = PAGE_SIZE;
> + }
It probably would be better to use ata_port_printk() and
printk_ratelimit() the message.
Thanks.
--
tejun
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