fuse: rework fuse_readpages()
fuse: rework fuse_readpages()

The patch uses 'nr_pages' argument of fuse_readpages() as heuristics for the
number of page pointers to allocate.

This can be improved further by taking in consideration fc->max_read and gaps
between page indices, but it's not clear whether it's worthy or not.

Signed-off-by: Maxim Patlasov <c8cfd11518263806e885f2c6a2b61e35d49e4229@parallels.com>
Signed-off-by: Miklos Szeredi <84cd5483a2f9acd1c37251cba7c2908448f221b8@suse.cz>

KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs