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Re: [PATCH v7 6/8] block: make BlockConf size props 32bit and accept size suffixes

On 5/28/20 4:39 PM, Roman Kagan wrote:
Convert all size-related properties in BlockConf to 32bit.  This will
allow to accomodate bigger block sizes (in a followup patch).

s/allow to accomodate/accommodate/

This also allows to make them all accept size suffixes, either via

Also, since min_io_size is exposed to the guest by scsi and virtio-blk
devices as an uint16_t in units of logical blocks, introduce an
additional check in blkconf_blocksizes to prevent its silent truncation.

Signed-off-by: Roman Kagan <rvkagan@xxxxxxxxxxxxxx>

+    if (conf->min_io_size / conf->logical_block_size > UINT16_MAX) {
+        error_setg(errp,
+                   "min_io_size must not exceed " stringify(UINT16_MAX)
+                   " logical blocks");

On my libc, this results in "must not exceed (65535) logical blocks".

Worse, I could envision a platform where it prints something funky like:

"exceed (2 * (32768) + 1) logical", based on however complex the definition of UINT16_MAX is. You're better off printing this one with %d than with stringify().

Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3226
Virtualization:  qemu.org | libvirt.org



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