configfs: consistent attribute size
The attribute store/show code currently limits attributes at PAGE_SIZE. This code comes from sysfs, where it still works that way. However, PAGE_SIZE is not constant. A 16k attribute string works on ia64 but not on x86. Really a subsystem shouldn't allow different attribute sizes based on platform. As such, limit all simple attributes to 4k. This works on all platforms, and is consistent with all current code. Signed-off-by: Joel Becker <joel.becker@oracle.com> Signed-off-by: Mark Fasheh <mark.fasheh@oracle.com>
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@ -33,6 +33,13 @@
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#include <linux/configfs.h>
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#include "configfs_internal.h"
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/*
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* A simple attribute can only be 4096 characters. Why 4k? Because the
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* original code limited it to PAGE_SIZE. That's a bad idea, though,
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* because an attribute of 16k on ia64 won't work on x86. So we limit to
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* 4k, our minimum common page size.
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*/
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#define SIMPLE_ATTR_SIZE 4096
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struct configfs_buffer {
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size_t count;
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@ -69,7 +76,7 @@ static int fill_read_buffer(struct dentry * dentry, struct configfs_buffer * buf
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count = ops->show_attribute(item,attr,buffer->page);
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buffer->needs_read_fill = 0;
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BUG_ON(count > (ssize_t)PAGE_SIZE);
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BUG_ON(count > (ssize_t)SIMPLE_ATTR_SIZE);
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if (count >= 0)
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buffer->count = count;
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else
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@ -137,8 +144,8 @@ fill_write_buffer(struct configfs_buffer * buffer, const char __user * buf, size
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if (!buffer->page)
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return -ENOMEM;
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if (count >= PAGE_SIZE)
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count = PAGE_SIZE - 1;
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if (count >= SIMPLE_ATTR_SIZE)
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count = SIMPLE_ATTR_SIZE - 1;
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error = copy_from_user(buffer->page,buf,count);
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buffer->needs_read_fill = 1;
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/* if buf is assumed to contain a string, terminate it by \0,
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