Re: [PATCH 1/2] megasas: use unsigned type for reply_queue_head

[P J P]

+-- On Tue, 12 May 2020, Peter Maydell wrote --+
| > +    uint16_t reply_queue_head;
| 
| Using a 16-bit type here means that code like this:
| 
|     s->reply_queue_head = ldl_le_pci_dma(pcid, s->producer_pa);
|     s->reply_queue_head %= MEGASAS_MAX_FRAMES;
| 
| suddenly does a truncation of the 32-bit loaded value before
| the modulus operation, which is a bit odd, though since
| MEGASAS_MAX_FRAMES happens to be a power of 2 the end
| result won't change.

Yes, 16-bit also for its range of value is limitted to MEGASAS_MAX_FRAMES=2048.
 
| It's also a bit weird to change reply_queue_head's type
| but not reply_queue_tail or reply_queue_len.

That's in the second patch.

Thank you.
--
Prasad J Pandit / Red Hat Product Security Team
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