Merge git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux-2.6-for-linus
* git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux-2.6-for-linus: lguest: update comments to reflect LHCALL_LOAD_GDT_ENTRY. virtio: console: Prevent userspace from submitting NULL buffers virtio: console: Fix poll blocking even though there is data to read
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4e24db5b1a
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@ -324,9 +324,8 @@ static void lguest_load_gdt(const struct desc_ptr *desc)
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}
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/*
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* For a single GDT entry which changes, we do the lazy thing: alter our GDT,
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* then tell the Host to reload the entire thing. This operation is so rare
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* that this naive implementation is reasonable.
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* For a single GDT entry which changes, we simply change our copy and
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* then tell the host about it.
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*/
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static void lguest_write_gdt_entry(struct desc_struct *dt, int entrynum,
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const void *desc, int type)
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@ -338,9 +337,13 @@ static void lguest_write_gdt_entry(struct desc_struct *dt, int entrynum,
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}
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/*
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* OK, I lied. There are three "thread local storage" GDT entries which change
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* There are three "thread local storage" GDT entries which change
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* on every context switch (these three entries are how glibc implements
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* __thread variables). So we have a hypercall specifically for this case.
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* __thread variables). As an optimization, we have a hypercall
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* specifically for this case.
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*
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* Wouldn't it be nicer to have a general LOAD_GDT_ENTRIES hypercall
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* which took a range of entries?
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*/
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static void lguest_load_tls(struct thread_struct *t, unsigned int cpu)
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{
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@ -596,6 +596,10 @@ static ssize_t port_fops_write(struct file *filp, const char __user *ubuf,
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ssize_t ret;
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bool nonblock;
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/* Userspace could be out to fool us */
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if (!count)
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return 0;
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port = filp->private_data;
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nonblock = filp->f_flags & O_NONBLOCK;
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@ -642,7 +646,7 @@ static unsigned int port_fops_poll(struct file *filp, poll_table *wait)
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poll_wait(filp, &port->waitqueue, wait);
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ret = 0;
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if (port->inbuf)
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if (!will_read_block(port))
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ret |= POLLIN | POLLRDNORM;
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if (!will_write_block(port))
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ret |= POLLOUT;
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