From: Mitchel Humpherys <mitchelh@codeaurora.org>
Date: Fri, 23 May 2014 20:01:22 +0000 (-0700)
Subject: staging: ion: WARN when the handle kmap_cnt is going to wrap around
X-Git-Tag: omap-for-v3.16/fixes-against-rc1~39^2~36^2~313
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=22f6b9789aef2e0b0b409b1d7708cc653540248c;p=pandora-kernel.git

staging: ion: WARN when the handle kmap_cnt is going to wrap around

There are certain client bugs (double unmap, for example) that can cause
the handle->kmap_cnt (an unsigned int) to wrap around from zero. This
causes problems when the handle is destroyed because we have:

        while (handle->kmap_cnt)
                ion_handle_kmap_put(handle);

which takes a long time to complete when kmap_cnt starts at ~0 and can
result in a watchdog timeout.

WARN and bail when kmap_cnt is about to wrap around from zero.

Signed-off-by: Mitchel Humpherys <mitchelh@codeaurora.org>
Acked-by: Colin Cross <ccross@android.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

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